This is Info file sh-utils.info, produced by Makeinfo-1.55 from the input file sh-utils.texi. START-INFO-DIR-ENTRY * Shell utilities: (sh-utils). GNU shell utilities. * basename: (sh-utils)basename invocation. Strip directory and suffix. * date: (sh-utils)date invocation. Print/set system date and time. * dirname: (sh-utils)dirname invocation. Strip non-directory suffix. * echo: (sh-utils)echo invocation. Print a line of text. * env: (sh-utils)env invocation. Modify the environment. * expr: (sh-utils)expr invocation. Evaluate expressions. * false: (sh-utils)false invocation. Do nothing, unsuccessfully. * groups: (sh-utils)groups invocation. Print group names a user is in. * hostname: (sh-utils)hostname invocation. Print or set system name. * id: (sh-utils)id invocation. Print real/effective uid/gid. * logname: (sh-utils)logname invocation. Print current login name. * nice: (sh-utils)nice invocation. Modify scheduling priority. * pathchk: (sh-utils)pathchk invocation. Check file name portability. * printenv: (sh-utils)printenv invocation. Print environment variables. * printf: (sh-utils)printf invocation. Format and print data. * pwd: (sh-utils)pwd invocation. Print working directory. * sleep: (sh-utils)sleep invocation. Delay for a specified time. * stty: (sh-utils)stty invocation. Print/change terminal settings. * su: (sh-utils)su invocation. Modify user and group id. * tee: (sh-utils)tee invocation. Redirect to multiple files. * test: (sh-utils)test invocation. File/string tests. * true: (sh-utils)true invocation. Do nothing, successfully. * tty: (sh-utils)tty invocation. Print terminal name. * uname: (sh-utils)uname invocation. Print system information. * users: (sh-utils)users invocation. Print current user names. * who: (sh-utils)who invocation. Print who is logged in. * whoami: (sh-utils)whoami invocation. Print effective user id. * yes: (sh-utils)yes invocation. Print a string indefinitely. END-INFO-DIR-ENTRY This file documents the GNU shell utilities. Copyright (C) 1994 Free Software Foundation, Inc. Permission is granted to make and distribute verbatim copies of this manual provided the copyright notice and this permission notice are preserved on all copies. Permission is granted to copy and distribute modified versions of this manual under the conditions for verbatim copying, provided that the entire resulting derived work is distributed under the terms of a permission notice identical to this one. Permission is granted to copy and distribute translations of this manual into another language, under the above conditions for modified versions, except that this permission notice may be stated in a translation approved by the Foundation. File: sh-utils.info, Node: Top, Next: Introduction, Prev: (DIR), Up: (DIR) GNU shell utilities ******************* This manual minimally documents version GNU sh-utils 1.12 of the GNU shell utilities. * Menu: * Introduction:: Caveats, overview, and authors. * Common options:: Common options. * Printing text:: echo printf yes * Conditions:: false true test expr * Redirection:: tee * File name manipulation:: dirname basename pathchk * Working context information:: pwd stty printenv tty * User information:: id logname whoami groups users who * System context:: date uname hostname * Modified command invocation:: env nice nohup su * Delaying:: sleep * Index:: General index. File: sh-utils.info, Node: Introduction, Next: Common options, Prev: Top, Up: Top Introduction ************ First of all, this manual is incomplete. The `stty' section, in particular, needs substantial reorganization and additional explanatory text before it will be up to the standard of other GNU manuals. Explanatory text in general is lacking; the manual presently assumes you pretty much know what to do, and just need to be reminded of how. Thus, if you are interested, please get involved in improving this manual. The entire GNU community will benefit. Some of these programs are useful only when writing shell scripts; utilities like these are, in fact, the "language" of shell scripts (to a great extent). Others are occasionally useful interactively. The GNU shell utilities are mostly compatible with the POSIX.2 standard. Please report bugs to `bug-gnu-utils@prep.ai.mit.edu'. Remember to include the version number, machine architecture, input files, and any other information needed to reproduce the bug. *Note Bugs: (gcc)Bugs. This manual is based on the Unix man pages in the distribution, which were originally written by David MacKenzie and updated by Jim Meyering. Franc,ois Pinard did the initial conversion to Texinfo format. Karl Berry did the indexing, some reorganization, and editing of the results. Richard Stallman contributed his usual invaluable insights to the overall process. File: sh-utils.info, Node: Common options, Next: Printing text, Prev: Introduction, Up: Top Common options ************** Certain options are available in all these programs. Rather than writing identical descriptions for each of the programs, they are described here. (In fact, every GNU program accepts (or should accept) these options.) Many of these programs take arbitrary strings as arguments. In those cases, `--help' and `--version' are taken as these options only if there is one and exactly one command line argument. `--help' Print a usage message listing all available options, then exit successfully. `--version' Print the version number, then exit successfully. File: sh-utils.info, Node: Printing text, Next: Conditions, Prev: Common options, Up: Top Printing text ************* This section describes commands that display text strings. * Menu: * echo invocation:: Print a line of text. * printf invocation:: Format and print data. * yes invocation:: Print a string until interrupted. File: sh-utils.info, Node: echo invocation, Next: printf invocation, Up: Printing text `echo': Print a line of text ============================ Synopsis: echo [ OPTION ]... [ STRING ]... `echo' writes each given STRING to standard output, with a space between each and a newline after the last one. The program accepts the following options. Also see *Note Common options::. Do not output the trailing newline. Enable interpretation of the following backslash-escaped characters in each STRING: `\a' alert (bell) `\b' backspace `\c' suppress trailing newline `\f' form feed `\n' new line `\r' carriage return `\t' horizontal tab `\v' vertical tab `\\' backslash `\NNN' the character whose ASCII code is NNN (octal); if NNN is not a valid octal number, it is printed literally. File: sh-utils.info, Node: printf invocation, Next: yes invocation, Prev: echo invocation, Up: Printing text `printf': Format and print data =============================== Synopsis: printf FORMAT [ ARGUMENT ]... `printf' prints the FORMAT string, interpreting `%' directives and `\' escapes in the same way as the C `printf' function. The FORMAT argument is re-used as necessary to convert all of the given ARGUMENTs. `printf' has one additional directive, `%b', which prints its argument string with `\' escapes interpreted in the same way as in the FORMAT string. `printf' interprets `\0ooo' in FORMAT as an octal number (if OOO is 0 to 3 octal digits) specifying a character to print, and `\xhhh' as a hexadecimal number (if HHH is 1 to 3 hex digits) specifying a character to print. An additional escape, `\c', causes `printf' to produce no further output. The only options are a lone `--help' or `--version'. *Note Common options::. File: sh-utils.info, Node: yes invocation, Prev: printf invocation, Up: Printing text `yes': Print a string until interrupted ======================================= `yes' prints the command line arguments, separated by spaces and followed by a newline, forever until it is killed. If no arguments are given, it prints `y' followed by a newline forever until killed. The only options are a lone `--help' or `--version'. *Note Common options::. File: sh-utils.info, Node: Conditions, Next: Redirection, Prev: Printing text, Up: Top Conditions ********** This section describes commands that are primarily useful for their exit status, rather than their output. Thus, they are often used as the condition of shell `if' statements, or as the last command in a pipeline. * Menu: * false invocation:: Do nothing, unsuccessfully. * true invocation:: Do nothing, successfully. * test invocation:: Check file types and compare values. * expr invocation:: Evaluate expressions. File: sh-utils.info, Node: false invocation, Next: true invocation, Up: Conditions `false': Do nothing, unsuccessfully =================================== `false' does nothing except return an exit status of 1, meaning "failure". It can be used as a place holder in shell scripts where an unsuccessful command is needed. Any arguments are ignored, except for a lone `--help' or `--version' (*note Common options::.). File: sh-utils.info, Node: true invocation, Next: test invocation, Prev: false invocation, Up: Conditions `true': Do nothing, successfully ================================ `true' does nothing except return an exit status of 0, meaning "success". It can be used as a place holder in shell scripts where a successful command is needed, although the shell built-in command `:' (colon) may be faster. Any arguments are ignored, except for a lone `--help' or `--version' (*note Common options::.). File: sh-utils.info, Node: test invocation, Next: expr invocation, Prev: true invocation, Up: Conditions `test': Check file types and compare values =========================================== `test' returns a status of 0 (true) or 1 (false) depending on the evaluation of the conditional expression EXPR. Each part of the expression must be a separate argument. `test' has file status checks, string operators, and numeric comparison operators. Because most shells have a built-in command by the same name, using the unadorned command name in a script or interactively may get you different functionality than that described here. Besides the options below, `test' accepts a lone `--help' or `--version'. *Note Common options::. A single non-option argument is also allowed: `test' returns true if the argument is not null. * Menu: * File type tests:: -[bcdfhLpSt] * Access permission tests:: -[gkruwxOG] * File characteristics tests:: -e -s -nt -ot -ef * String tests:: -z -n = != * Numeric tests:: -eq -ne -lt -le -gt -ge * Connectives for test:: ! -a -o File: sh-utils.info, Node: File type tests, Next: Access permission tests, Up: test invocation File type tests --------------- These options test for particular types of files. (Everything's a file, but not all files are the same!) `-b FILE' True if FILE exists and is a block special device. `-c FILE' True if FILE exists and is a character special device. `-d FILE' True if FILE exists and is a directory. `-f FILE' True if FILE exists and is a regular file. `-h FILE' `-L FILE' True if FILE exists and is a symbolic link. `-p FILE' True if FILE exists and is a named pipe. `-S FILE' True if FILE exists and is a socket. `-t [ FD ]' True if FD is opened on a terminal. If FD is omitted, it defaults to 1 (standard output). File: sh-utils.info, Node: Access permission tests, Next: File characteristics tests, Prev: File type tests, Up: test invocation Access permission tests ----------------------- These options test for particular access permissions. `-g FILE' True if FILE exists and has its set-group-id bit set. `-k FILE' True if FILE has its "sticky" bit set. `-r FILE' True if FILE exists and is readable. `-u FILE' True if FILE exists and has its set-user-id bit set. `-w FILE' True if FILE exists and is writable. `-x FILE' True if FILE exists and is executable. `-O FILE' True if FILE exists and is owned by the current effective user id. `-G FILE' True if FILE exists and is owned by the current effective group id. File: sh-utils.info, Node: File characteristics tests, Next: String tests, Prev: Access permission tests, Up: test invocation File characteristics tests -------------------------- These options test other file characteristics. `-e FILE' True if FILE exists. `-s FILE' True if FILE exists and has a size greater than zero. `FILE1 -nt FILE2' True if FILE1 is newer (according to modification date) than FILE2. `FILE1 -ot FILE2' True if FILE1 is older (according to modification date) than FILE2. `FILE1 -ef FILE2' True if FILE1 and FILE2 have the same device and inode numbers, i.e., if they are hard links to each other. File: sh-utils.info, Node: String tests, Next: Numeric tests, Prev: File characteristics tests, Up: test invocation String tests ------------ These options test string characteristics. Strings are not quoted for `test', though you may need to quote them to protect characters with special meaning to the shell, e.g., spaces. `-z STRING' True if the length of STRING is zero. `-n STRING' `STRING' True if the length of STRING is non-zero. `STRING1 = STRING2' True if the strings are equal. `STRING1 != STRING2' True if the strings are not equal. File: sh-utils.info, Node: Numeric tests, Next: Connectives for test, Prev: String tests, Up: test invocation Numeric tests ------------- Numeric relationals. The arguments must be entirely numeric (possibly negative), or the special expression `-l STRING', which evaluates to the length of STRING. `ARG1 -eq ARG2' `ARG1 -ne ARG2' `ARG1 -lt ARG2' `ARG1 -le ARG2' `ARG1 -gt ARG2' `ARG1 -ge ARG2' These arithmetic binary operators return true if ARG1 is equal, not-equal, less-than, less-than-or-equal, greater-than, or greater-than-or-equal than ARG2, respectively. For example: test -1 -gt -2 && echo yes => yes test -l abc -gt 1 && echo yes => yes test 0x100 -eq 1 error--> test: integer expression expected before -eq File: sh-utils.info, Node: Connectives for test, Prev: Numeric tests, Up: test invocation Connectives for `test' ---------------------- The usual logical connectives. `! EXPR' True if EXPR is false. `EXPR1 -a EXPR2' True if both EXPR1 and EXPR2 are true. `EXPR1 -o EXPR2' True if either EXPR1 or EXPR2 is true. File: sh-utils.info, Node: expr invocation, Prev: test invocation, Up: Conditions `expr': Evaluate expressions ============================ `expr' evaluates an expression and writes the result on standard output. Each token of the expression must be a separate argument. Operands are either numbers or strings. `expr' coerces anything appearing in an operand position to an integer or a string depending on the operation being applied to it. Strings are not quoted for `expr', though you may need to quote them to protect characters with special meaning to the shell, e.g., spaces. Operators may given as infix symbols or prefix keywords. Parentheses may be used for grouping in the usual manner (you must quote parentheses to avoid the shell evaluating them, however). Exit status: 0 if the expression is neither null nor 0, 1 if the expression is null or 0, 2 for invalid expressions. * Menu: * Relations for expr:: | & < <= = == != >= > * Numeric expressions:: + - * / % * String expressions:: : match substr index length * Examples of expr:: Examples. File: sh-utils.info, Node: Relations for expr, Next: Numeric expressions, Up: expr invocation Relations for `expr' -------------------- The usual logical connectives and relations, in order of precedence. Yields its first argument if it is neither null nor 0, otherwise its second argument. Yields its first argument if neither argument is null or 0, otherwise 0. `< <= = == != >= >' Compare the arguments and return 1 if the relation is true, 0 otherwise. `==' is a synonym for `='. `expr' first tries to coerce both arguments to numbers and do a numeric comparison; if either coercion fails, it does a lexicographic comparison. File: sh-utils.info, Node: Numeric expressions, Next: String expressions, Prev: Relations for expr, Up: expr invocation Numeric expressions ------------------- Numeric operators, in order of increasing precedence. The connectives (previous section) have higher precedence, the string operators (following section) have lower. `+ -' Addition and subtraction. Both arguments are coerced to numbers; an error occurs if this cannot be done. `* / %' Multiplication, division, remainder. Both arguments are coerced to numbers; an error occurs if this cannot be done. File: sh-utils.info, Node: String expressions, Next: Examples of expr, Prev: Numeric expressions, Up: expr invocation String expressions ------------------ String operators. These have lowest precedence. `STRING : REGEX' Perform pattern matching. The arguments are coerced to strings and the second is considered to be a (basic, a la `grep') regular expression, with a `^' implicitly prepended. The first argument is then matched against this regular expression. If the match succeeds and REGEX uses `\(' and `\)', the `:' expression returns the part of STRING that matched the subexpression; otherwise, it returns the number of characters matched. If the match fails, the `:' operator returns the null string if `\(' and `\)' are used in REGEX, otherwise 0. Only the first `\( ... \)' pair is relevant to the return value; additional pairs are meaningful only for grouping the regular expression operators. *Note Regular Expression Library: (regex)Top, for details of regular expression syntax. `match STRING REGEX' An alternative way to do pattern matching. This is the same as `STRING : REGEX'. `substr STRING POSITION LENGTH' Returns the substring of STRING beginning at POSITION with length at most LENGTH. If either POSITION or LENGTH is negative or non-numeric, returns the null string. `index STRING CHARACTER-CLASS' Returns the first position in STRING where the first character in CHARSET was found. If no character in CHARSET is found in STRING, return 0. `length STRING' Returns the length of STRING. The keywords cannot be used as strings. File: sh-utils.info, Node: Examples of expr, Prev: String expressions, Up: expr invocation Examples of `expr' ------------------ Here are a few examples, including quoting for shell metacharacters. To add 1 to the shell variable `foo', in Bourne-compatible shells: foo=`expr $foo + 1` To print the non-directory part of the file name stored in `$fname', which need not contain a `/'. expr $fname : '.*/\(^.*\)' '^|' $fname expr abc : 'a\(.\)c' => b expr index abcdef cz => 3 expr index index a error--> expr: syntax error File: sh-utils.info, Node: Redirection, Next: File name manipulation, Prev: Conditions, Up: Top Redirection *********** Unix shells commonly provide several forms of "redirection"--ways to change the input source or output destination of a command. But one useful redirection is performed by a separate command, not by the shell; it's described here. * Menu: * tee invocation:: Redirect output to multiple files. File: sh-utils.info, Node: tee invocation, Up: Redirection `tee': Redirect output to multiple files ======================================== The `tee' command copies standard input to standard output and also to any files given as arguments. This is useful when you want not only to send some data down a pipe, but also to save a copy. Synopsis: tee [ OPTION ]... [ FILE ]... If a file being written to does not already exist, it is created. If a file being written to already exists, the data it previously contained is overwritten unless the `-a' option is used. The program accepts the following options. Also see *Note Common options::. `--append' Append standard input to the given files rather than overwriting them. `--ignore-interrupts' Ignore interrupt signals. File: sh-utils.info, Node: File name manipulation, Next: Working context information, Prev: Redirection, Up: Top File name manipulation ********************** This section describes commands that manipulate file names. * Menu: * basename invocation:: Strip directory and suffix from a file name. * dirname invocation:: Strip non-directory suffix from a file name. * pathchk invocation:: Check file name portability. File: sh-utils.info, Node: basename invocation, Next: dirname invocation, Up: File name manipulation `basename': Strip directory and suffix from a file name ======================================================= Synopsis: basename NAME [ SUFFIX ] The `basename' command removes any leading directory components from NAME. If SUFFIX is specified and is identical to the end of NAME, it is removed from NAME as well. `basename' prints the result on standard output. The only options are `--help' and `--version'. *Note Common options::. File: sh-utils.info, Node: dirname invocation, Next: pathchk invocation, Prev: basename invocation, Up: File name manipulation `dirname': Strip non-directory suffix from a file name ====================================================== Synopsis: dirname NAME `dirname' prints all but the final slash-delimited component of NAME. If NAME is a single component, `dirname' prints `.' (meaning the current directory). The only options are `--help' and `--version'. *Note Common options::. File: sh-utils.info, Node: pathchk invocation, Prev: dirname invocation, Up: File name manipulation `pathchk': Check file name portability ====================================== Synopsis: pathchk [ OPTION ]... NAME... For each NAME, `pathchk' prints a message if any of these conditions is true: 1. one of the existing directories in NAME does not have search (execute) permission, 2. the length of NAME is larger than its filesystem's maximum file name length, 3. the length of one component of NAME, corresponding to an existing directory name, is larger than its filesystem's maximum length for a file name component. The program accepts the following option. Also see *Note Common options::. `--portability' Instead of performing length checks on the underlying filesystem, test the length of each file name and its components against the POSIX.1 minimum limits for portability. Also check that the file name contains no characters not in the portable file name character set. Exit status: 0 if all specified file names passed all of the tests, 1 otherwise. File: sh-utils.info, Node: Working context information, Next: User information, Prev: File name manipulation, Up: Top Working context information *************************** This section describes commands that display or alter the context in which you are working: the current directory, the terminal settings, and so forth. See also the user-related commands in the next section. * Menu: * pwd invocation:: Print working directory. * stty invocation:: Print or change terminal characteristics. * printenv invocation:: Print environment variables. * tty invocation:: Print file name of terminal on standard input. File: sh-utils.info, Node: pwd invocation, Next: stty invocation, Up: Working context information `pwd': Print working directory ============================== `pwd' prints the fully resolved name of the current directory. That is, all components of the printed name will be actual directory names--none will be symbolic links. Because most shells have a built-in command by the same name, using the unadorned command name in a script or interactively may get you different functionality than that described here. The only options are a lone `--help' or `--version'. *Note Common options::. File: sh-utils.info, Node: stty invocation, Next: printenv invocation, Prev: pwd invocation, Up: Working context information `stty': Print or change terminal characteristics ================================================ If given no arguments, `stty' prints the baud rate, line discipline number (on systems that support it), and line settings that have been changed from the values set by `stty sane'. Mode reading and setting are performed on the tty line connected to standard input. `stty' accepts many non-option arguments that change aspects of the terminal line operation, as described below. Synopses: stty [ SETTING ]... stty [ OPTION ] The program accepts the following options. Also see *Note Common options::. `--all' Print all current settings in human-readable form. `--save' Print all current settings in a form that can be used as an argument to another `stty' command to restore the current settings. Many settings can be turned off by preceding them with a `-'. Such arguments are marked below with "May be negated" in their description. The descriptions themselves refer to the positive case, that is, when *not* negated (unless stated otherwise, of course). Some settings are not available on all POSIX systems, since they use extensions. Such arguments are marked below with "Non-POSIX" in their description. On non-POSIX systems, those or other settings also may not be available, but it's not feasible to document all the variations: just try it and see. * Menu: * Control:: Control settings * Input:: Input settings * Output:: Output settings * Local:: Local settings * Combination:: Combination settings * Characters:: Special characters * Special:: Special settings File: sh-utils.info, Node: Control, Next: Input, Up: stty invocation Control settings ---------------- Control settings: `parenb' Generate parity bit in output and expect parity bit in input. May be negated. `parodd' Set odd parity (even if negated). May be negated. `cs5' `cs6' `cs7' `cs8' Set character size to 5, 6, 7, or 8 bits. `hup' `hupcl' Send a hangup signal when the last process closes the tty. May be negated. `cstopb' Use two stop bits per character (one if negated). May be negated. `cread' Allow input to be received. May be negated. `clocal' Disable modem control signals. May be negated. `crtscts' Enable RTS/CTS flow control. Non-POSIX. May be negated. File: sh-utils.info, Node: Input, Next: Output, Prev: Control, Up: stty invocation Input settings -------------- `ignbrk' Ignore breaks. May be negated. `brkint' Make breaks cause an interrupt signal. May be negated. `ignpar' Ignore parity errors. May be negated. `parmrk' Mark parity errors (with a 255-0-character sequence). May be negated. `inpck' Enable input parity checking. May be negated. `istrip' Clear high (8th) bit of input characters. May be negated. `inlcr' Translate newline to carriage return. May be negated. `igncr' Ignore carriage return. May be negated. `icrnl' Translate carriage return to newline. May be negated. `ixon' Enable XON/XOFF flow control (that is, CTRL-s/CTRL-Q). May be negated. `ixoff' `tandem' Enable sending of `stop' character when the system input buffer is almost full, and `start' character when it becomes almost empty again. May be negated. `iuclc' Translate uppercase characters to lowercase. Non-POSIX. May be negated. `ixany' Allow any character to restart output (only the start character if negated). Non-POSIX. May be negated. `imaxbel' Enable beeping and not flushing input buffer if a character arrives when the input buffer is full. Non-POSIX. May be negated. File: sh-utils.info, Node: Output, Next: Local, Prev: Input, Up: stty invocation Output settings --------------- These arguments specify output-related operations. `opost' Postprocess output. May be negated. `olcuc' Translate lowercase characters to uppercase. Non-POSIX. May be negated. `ocrnl' Translate carriage return to newline. Non-POSIX. May be negated. `onlcr' Translate newline to carriage return-newline. Non-POSIX. May be negated. `onocr' Do not print carriage returns in the first column. Non-POSIX. May be negated. `onlret' Newline performs a carriage return. Non-POSIX. May be negated. `ofill' Use fill (padding) characters instead of timing for delays. Non-POSIX. May be negated. `ofdel' Use delete characters for fill instead of null characters. Non-POSIX. May be negated. `nl1' `nl0' Newline delay style. Non-POSIX. `cr3' `cr2' `cr1' `cr0' Carriage return delay style. Non-POSIX. `tab3' `tab2' `tab1' `tab0' Horizontal tab delay style. Non-POSIX. `bs1' `bs0' Backspace delay style. Non-POSIX. `vt1' `vt0' Vertical tab delay style. Non-POSIX. `ff1' `ff0' Form feed delay style. Non-POSIX. File: sh-utils.info, Node: Local, Next: Combination, Prev: Output, Up: stty invocation Local settings -------------- `isig' Enable `interrupt', `quit', and `suspend' special characters. May be negated. `icanon' Enable `erase', `kill', `werase', and `rprnt' special characters. May be negated. `iexten' Enable non-POSIX special characters. May be negated. `echo' Echo input characters. May be negated. `echoe' `crterase' Echo `erase' characters as backspace-space-backspace. May be negated. `echok' Echo a newline after a `kill' character. May be negated. `echonl' Echo newline even if not echoing other characters. May be negated. `noflsh' Disable flushing after `interrupt' and `quit' special characters. May be negated. `xcase' Enable input and output of uppercase characters by preceding their lowercase equivalents with `\', when `icanon' is set. Non-POSIX. May be negated. `tostop' Stop background jobs that try to write to the terminal. Non-POSIX. May be negated. `echoprt' `prterase' Echo erased characters backward, between `\' and `/'. Non-POSIX. May be negated. `echoctl' `ctlecho' Echo control characters in hat notation (`^C') instead of literally. Non-POSIX. May be negated. `echoke' `crtkill' Echo the `kill' special character by erasing each character on the line as indicated by the `echoprt' and `echoe' settings, instead of by the `echoctl' and `echok' settings. Non-POSIX. May be negated. File: sh-utils.info, Node: Combination, Next: Characters, Prev: Local, Up: stty invocation Combination settings -------------------- Combination settings: `evenp' `parity' Same as `parenb -parodd cs7'. May be negated. If negated, same as `-parenb cs8'. `oddp' Same as `parenb parodd cs7'. May be negated. If negated, same as `-parenb cs8'. Same as `-icrnl -onlcr'. May be negated. If negated, same as `icrnl -inlcr -igncr onlcr -ocrnl -onlret'. Reset the `erase' and `kill' special characters to their default values. `sane' Same as: cread -ignbrk brkint -inlcr -igncr icrnl -ixoff -iuclc -ixany imaxbel opost -olcuc -ocrnl onlcr -onocr -onlret -ofill -ofdel nl0 cr0 tab0 bs0 vt0 ff0 isig icanon iexten echo echoe echok -echonl -noflsh -xcase -tostop -echoprt echoctl echoke and also sets all special characters to their default values. `cooked' Same as `brkint ignpar istrip icrnl ixon opost isig icanon', plus sets the `eof' and `eol' characters to their default values if they are the same as the `min' and `time' characters. May be negated. If negated, same as `raw'. `raw' Same as: -ignbrk -brkint -ignpar -parmrk -inpck -istrip -inlcr -igncr -icrnl -ixon -ixoff -iuclc -ixany -imaxbel -opost -isig -icanon -xcase min 1 time 0 May be negated. If negated, same as `cooked'. `cbreak' Same as `-icanon'. May be negated. If negated, same as `icanon'. `pass8' Same as `-parenb -istrip cs8'. May be negated. If negated, same as `parenb istrip cs7'. `litout' Same as `-parenb -istrip -opost cs8'. May be negated. If negated, same as `parenb istrip opost cs7'. `decctlq' Same as `-ixany'. Non-POSIX. May be negated. `tabs' Same as `tab0'. Non-POSIX. May be negated. If negated, same as `tab3'. `lcase' `LCASE' Same as `xcase iuclc olcuc'. Non-POSIX. May be negated. `crt' Same as `echoe echoctl echoke'. `dec' Same as `echoe echoctl echoke -ixany intr ^C erase ^? kill C-u'. File: sh-utils.info, Node: Characters, Next: Special, Prev: Combination, Up: stty invocation Special characters ------------------ The special characters' default values vary from system to system. They are set with the syntax `name value', where the names are listed below and the value can be given either literally, in hat notation (`^C'), or as an integer which may start with `0x' to indicate hexadecimal, `0' to indicate octal, or any other digit to indicate decimal. For GNU stty, giving a value of `^-' or `undef' disables that special character. (This is incompatible with Ultrix `stty', which uses a value of `u' to disable a special character. GNU `stty' treats a value `u' like any other, namely to set that special character to u.) `intr' Send an interrupt signal. `quit' Send a quit signal. `erase' Erase the last character typed. `kill' Erase the current line. `eof' Send an end of file (terminate the input). `eol' End the line. `eol2' Alternate character to end the line. Non-POSIX. `swtch' Switch to a different shell layer. Non-POSIX. `start' Restart the output after stopping it. `stop' Stop the output. `susp' Send a terminal stop signal. `dsusp' Send a terminal stop signal after flushing the input. Non-POSIX. `rprnt' Redraw the current line. Non-POSIX. `werase' Erase the last word typed. Non-POSIX. `lnext' Enter the next character typed literally, even if it is a special character. Non-POSIX. File: sh-utils.info, Node: Special, Prev: Characters, Up: stty invocation Special settings ---------------- `min N' Set the minimum number of characters that will satisfy a read until the time value has expired, when `-icanon' is set. `time N' Set the number of tenths of a second before reads time out if the min number of characters have not been read, when `-icanon' is set. `ispeed N' Set the input speed to N. `ospeed N' Set the output speed to N. `rows N' Tell the tty kernel driver that the terminal has N rows. Non-POSIX. `cols N' `columns N' Tell the kernel that the terminal has N columns. Non-POSIX. `size' Print the number of rows and columns that the kernel thinks the terminal has. (Systems that don't support rows and cols in the kernel typically use the environment variables `LINES' and `COLUMNS' instead; however, GNU `stty' does not know anything about them.) Non-POSIX. `line N' Use line discipline N. Non-POSIX. `speed' Print the terminal speed. Set the input and output speeds to N. N can be one of: 0 50 75 110 134 134.5 150 200 300 600 1200 1800 2400 4800 9600 19200 38400 `exta' `extb'. `exta' is the same as 19200; `extb' is the same as 38400. 0 hangs up the line if `-clocal' is set. File: sh-utils.info, Node: printenv invocation, Next: tty invocation, Prev: stty invocation, Up: Working context information `printenv': Print all or some environment variables =================================================== Synopsis: printenv [ OPTION ] [ VARIABLE ]... If no VARIABLEs are specified, `printenv' prints the value of every environment variable. Otherwise, it prints the value of each VARIABLE that is set, and nothing for those that are not set. The only options are a lone `--help' or `--version'. *Note Common options::. Exit status: 0 if all variables specified were found 1 if at least one specified variable was not found 2 if a write error occurred File: sh-utils.info, Node: tty invocation, Prev: printenv invocation, Up: Working context information `tty': Print file name of terminal on standard input ==================================================== `tty' prints the file name of the tty connected to its standard input. It prints `not a tty' if standard input is not a tty. Synopsis: tty [ OPTION ]... The program accepts the following option. Also see *Note Common options::. `--silent' `--quiet' Print nothing; only return an exit status. Exit status: 0 if standard input is a tty 1 if standard input is not a tty 2 if given incorrect arguments 3 if a write error occurs File: sh-utils.info, Node: User information, Next: System context, Prev: Working context information, Up: Top User information **************** This section describes commands that print user-related information: logins, groups, and so forth. * Menu: * id invocation:: Print real and effective uid and gid. * logname invocation:: Print current login name. * whoami invocation:: Print effective user id. * groups invocation:: Print group names a user is in. * users invocation:: Print login names of users currently logged in. * who invocation:: Print who is currently logged in. File: sh-utils.info, Node: id invocation, Next: logname invocation, Up: User information `id': Print real and effective uid and gid ========================================== `id' prints information about the given user, or the process running it if no user is specified. Synopsis: id [ OPTION ]... [ USERNAME ] By default, it prints the real user id, real group id, effective user id if different from the real user id, effective group id if different from the real group id, and supplemental group ids. Each of these numeric values is preceded by an identifying string and followed by the corresponding user or group name in parentheses. The options cause `id' to print only part of the above information. Also see *Note Common options::. `--group' Print only the group id. `--groups' Print only the supplementary groups. `--name' Print the user or group name instead of the ID number. Requires `-u', `-g', or `-G'. `--real' Print the real, instead of effective, user or group id. Requires `-u', `-g', or `-G'. `--user' Print only the user id. File: sh-utils.info, Node: logname invocation, Next: whoami invocation, Prev: id invocation, Up: User information `logname': Print current login name =================================== `logname' prints the calling user's name, as found in the file `/etc/utmp', and exits with a status of 0. If there is no `/etc/utmp' entry for the calling process, `logname' prints an error message and exits with a status of 1. The only options are `--help' and `--version'. *Note Common options::. File: sh-utils.info, Node: whoami invocation, Next: groups invocation, Prev: logname invocation, Up: User information `whoami': Print effective user id ================================= `whoami' prints the user name associated with the current effective user id. It is equivalent to the command `id -un'. The only options are `--help' and `--version'. *Note Common options::. File: sh-utils.info, Node: groups invocation, Next: users invocation, Prev: whoami invocation, Up: User information `groups': Print group names a user is in ======================================== `groups' prints the names of the primary and any supplementary groups that each given USERNAME, or the current process if none are given, is in. If user names are given, the name of each user is printed before the list of that user's groups. Synopsis: groups [ USERNAME ]... The group lists are equivalent to the output of the command `id -Gn'. The only options are `--help' and `--version'. *Note Common options::. File: sh-utils.info, Node: users invocation, Next: who invocation, Prev: groups invocation, Up: User information `users': Print login names of users currently logged in ======================================================= `users' prints on a single line a blank-separated list of user names of users currently logged in to the current host. Each user name corresponds to a login session, so if a user has more than one login session, that user's name will appear the same number of times in the output. Synopsis: users [ FILE ] With no FILE argument, `users' extracts its information from the file `/etc/utmp'. If a file argument is given, `users' uses that file instead. A common choice is `/etc/wtmp'. The only options are `--help' and `--version'. *Note Common options::. File: sh-utils.info, Node: who invocation, Prev: users invocation, Up: User information `who': Print who is currently logged in ======================================= Synopsis: `who' [ OPTION ] [ FILE ] [ am i ] If given no non-option arguments, `who' prints the following information for each user currently logged on: login name, terminal line, login time, and remote hostname or X display. If given one non-option argument, `who' uses that instead of `/etc/utmp' as the name of the file containing the record of users logged on. `/etc/wtmp' is commonly given as an argument to `who' to look at who has previously logged on. If given two non-option arguments, `who' prints only the entry for the user running it (determined from its standard input), preceded by the hostname. Traditionally, the two arguments given are `am i', as in `who am i'. The program accepts the following options. Also see *Note Common options::. Same as `who am i'. `--count' Print only the login names and the number of users logged on. Overrides all other options. Ignored; for compatibility with other versions of `who'. `--idle' After the login time, print the number of hours and minutes that the user has been idle. `.' means the user was active in last minute. `old' means the user was idle for more than 24 hours. `--heading' Print a line of column headings. `--mesg' `--message' `--writable' After each login name print a character indicating the user's message status: `+' allowing `write' messages `-' disallowing `write' messages `?' cannot find terminal device File: sh-utils.info, Node: System context, Next: Modified command invocation, Prev: User information, Up: Top System context ************** This section describes commands that print or change system-wide information. * Menu: * date invocation:: Print or set system date and time. * uname invocation:: Print system information. * hostname invocation:: Print or set system name. File: sh-utils.info, Node: date invocation, Next: uname invocation, Up: System context `date': Print or set system date and time ========================================= `date' with no arguments prints the current time and date, in the format of the `%c' directive (described below). Synopses: date [ OPTION ]... [ +FORMAT ] date [ -u|--utc|--universal ] [ MMDDHHMM[[CC]YY][.SS] ] If given an argument that starts with a `+', `date' prints the current time and date (or the time and date specified by the `--date' option, see below) in the format defined by that argument, which is the same as in the `strftime' function. Except for directives, which start with `%', characters in the format string are printed unchanged. The directives are described below. By default, `date' pads numeric fields with zeroes. GNU `date' recognizes the following numeric modifiers between the `%' and the directive. These are GNU extensions. (hyphen) do not pad the field (underscore) pad the field with spaces * Menu: * Time directives:: %[HIklMprsSTXZ] * Date directives:: %[aAbBcdDhjmUwWxyY] * Literal directives:: %[%nt] * Setting the time:: Changing the system clock. * Options for date:: Instead of the current time. * Examples of date:: Examples. File: sh-utils.info, Node: Time directives, Next: Date directives, Up: date invocation Time directives --------------- `date' directives related to times. hour (00...23) hour (01...12) hour ( 0...23) hour ( 1...12) minute (00...59) locale's AM or PM time, 12-hour (hh:mm:ss [AP]M) seconds since the epoch, i.e., 1 January 1970 00:00:00 UTC (a GNU extension) second (00...61) time, 24-hour (hh:mm:ss) locale's time representation (%H:%M:%S) time zone (e.g., EDT), or nothing if no time zone is determinable File: sh-utils.info, Node: Date directives, Next: Literal directives, Prev: Time directives, Up: date invocation Date directives --------------- `date' directives related to dates. locale's abbreviated weekday name (Sun...Sat) locale's full weekday name, variable length (Sunday...Saturday) locale's abbreviated month name (Jan...Dec) locale's full month name, variable length (January...December) locale's date and time (Sat Nov 04 12:02:33 EST 1989) day of month (01...31) date (mm/dd/yy) same as %b day of year (001...366) month (01...12) week number of year with Sunday as first day of week (00...53) day of week (0...6) with 0 corresponding to Sunday week number of year with Monday as first day of week (00...53) locale's date representation (mm/dd/yy) last two digits of year (00...99) year (1970....) File: sh-utils.info, Node: Literal directives, Next: Setting the time, Prev: Date directives, Up: date invocation Literal directives ------------------ `date' directives that produce literal strings. a literal % a newline a horizontal tab File: sh-utils.info, Node: Setting the time, Next: Options for date, Prev: Literal directives, Up: date invocation Setting the time ---------------- If given an argument that does not start with `+', `date' sets the system clock to the time and date specified by that argument (as described below). You must have appropriate privileges to set the system clock. The `--date' and `--set' options may not be used with such an argument. The `--universal' option may be used with such an argument to indicate that the specified time and date are relative to Coordinated Universal Time rather than to the local time zone. The argument must consist entirely of digits, which have the following meaning: month day within month hour minute first two digits of year (optional) last two digits of year (optional) second (optional) The `--set' option also sets the system clock; see the next section. File: sh-utils.info, Node: Options for date, Next: Examples of date, Prev: Setting the time, Up: date invocation Options for `date' ------------------ The program accepts the following options. Also see *Note Common options::. `-d DATESTR' `--date=DATESTR' Display the time and date specified in DATESTR instead of the current time and date. DATESTR can be in almost any common format. It can contain month names, timezones, `am' and `pm', `yesterday', `ago', `next', etc. The source file `getdate.y' implements this parsing for all GNU routines; we need precise documentation! `-f DATEFILE' `--file=DATEFILE' Parse each line in DATEFILE as with `-d' and display the resulting time and date. If DATEFILE is `-', use standard input. This is useful when you have many dates to process, because the system overhead of starting up the `date' executable many times can be considerable. `-s DATESTR' `--set=DATESTR' Set the time and date to DATESTR, See `-d' above. `--utc' `--universal' Print or set the time and date in Universal Coordinated Time instead of in local (wall clock) time. File: sh-utils.info, Node: Examples of date, Prev: Options for date, Up: date invocation Examples of `date' ------------------ Here are a few examples. Also see the documentation for the `-d' option in the previous section. * To print the date of the day before yesterday: date --date='2 days ago' * To print the date of the day three months and one day hence: date --date='3 months 1 day' * To print the day of year of Christmas in the current year: date --date='25 Dec' +%j * To print the current full month name and the day of the month: date '+%B %d' But this may not be what you want because for the first nine days of the month, the `%d' expands to a zero-padded two-digit field, for example `date -d 1may '+%B %d'' will print `May 01'. * To print a date without the leading zero for one-digit days of the month, you can use the (GNU extension) `-' modifier to suppress the padding altogether. date -d=1may '+%B %-d' * To print the current date and time in the format required by many non-GNU versions of `date' when setting the system clock: date +%m%d%H%M%Y.%S * To set the system clock forward by two minutes: date --set='+2 minutes' File: sh-utils.info, Node: uname invocation, Next: hostname invocation, Prev: date invocation, Up: System context `uname': Print system information ================================= `uname' prints information about the machine and operating system it is run on. If no options are given, `uname' acts as if the `-s' option were given. Synopsis: uname [ OPTION ]... If multiple options or `-a' are given, the selected information is printed in this order: SYSNAME NODENAME RELEASE OSVERSION MACHINE The OSVERSION, at least, may well be multiple words. For example: bash$ uname -a => Linux hayley 1.0.4 #3 Thu May 12 18:06:34 1994 i486 The program accepts the following options. Also see *Note Common options::. `--all' Print all of the below information. `--machine' Print the machine (hardware) type. `--nodename' Print the machine's network node hostname. `--release' Print the operating system release. `--sysname' Print the operating system name. Print the operating system version. File: sh-utils.info, Node: hostname invocation, Prev: uname invocation, Up: System context `hostname': Print or set system name ==================================== With no arguments, `hostname' prints the name of the current host system. With one argument, it sets the current host name to the specified string. You must have appropriate privileges to set the host name. Synopsis: hostname [ NAME ] The only options are `--help' and `--version'. *Note Common options::. File: sh-utils.info, Node: Modified command invocation, Next: Delaying, Prev: System context, Up: Top Modified command invocation *************************** This section describes commands that run other commands in some context different than the current one: a modified environment, as a different user, etc. * Menu: * env invocation:: Modify environment variables. * nice invocation:: Modify scheduling priority. * nohup invocation:: Immunize to hangups. * su invocation:: Modify user and group id. File: sh-utils.info, Node: env invocation, Next: nice invocation, Up: Modified command invocation `env': Run a command in a modified environment ============================================== `env' runs a command with an environment modified as specified by the command line arguments. Synopses: env [ OPTION ]... [ NAME=VALUE ]... [ COMMAND [ ARGS ]... ] env Arguments of the form `VARIABLE=VALUE' set the environment variable VARIABLE to value VALUE. VALUE may be empty (`VARIABLE='). Setting a variable to an empty value is different from unsetting it. The first remaining argument specifies the program name to invoke; it is searched for according to the `PATH' environment variable. Any remaining arguments are passed as arguments to that program. If no command name is specified following the environment specifications, the resulting environment is printed. This is like specifying a command name of `printenv'. The program accepts the following options. Also see *Note Common options::. `-u NAME' `--unset=NAME' Remove variable NAME from the environment, if it was in the environment. `--ignore-environment' Start with an empty environment, ignoring the inherited environment. File: sh-utils.info, Node: nice invocation, Next: nohup invocation, Prev: env invocation, Up: Modified command invocation `nice': Run a command with modified scheduling priority ======================================================= If no arguments are given, `nice' prints the current scheduling priority, which it inherited. Otherwise, `nice' runs the given COMMAND with its scheduling priority adjusted. If no ADJUSTMENT is given, the priority of the command is incremented by 10. You must have appropriate privileges to specify a negative adjustment. The priority can be adjusted by `nice' over the range of -20 (the highest priority) to 19 (the lowest). Synopsis: nice [ OPTION ]... [ COMMAND [ ARG ]... ] Because most shells have a built-in command by the same name, using the unadorned command name in a script or interactively may get you different functionality than that described here. The program accepts the following option. Also see *Note Common options::. `-n ADJUSTMENT' `-ADJUSTMENT' `--adjustment=ADJUSTMENT' Add ADJUSTMENT instead of 10 to the command's priority. File: sh-utils.info, Node: nohup invocation, Next: su invocation, Prev: nice invocation, Up: Modified command invocation `nohup': Run a command immune to hangups ======================================== `nohup' runs the given COMMAND with hangup signals ignored, so that the command can continue running in the background after you log out. Synopsis: nohup COMMAND [ ARG ]... Also, the scheduling priority is increased by 5. If standard output is a tty, it and standard error are redirected so that they are appended to the file `nohup.out'; if that cannot be written to, they are appended to the file `$HOME/nohup.out'. If that cannot be written to, the command is not run. If `nohup' creates either `nohup.out' or `$HOME/nohup.out', it creates it with no "group" or "other" access permissions. It does not change the permissions if the output file already existed. `nohup' does not automatically put the command it runs in the background; you must do that explicitly, by ending the command line with an `&'. The only options are `--help' and `--version'. *Note Common options::. File: sh-utils.info, Node: su invocation, Prev: nohup invocation, Up: Modified command invocation `su': Run a command with substitute user and group id ===================================================== `su' allows one user to temporarily become another user. It runs a command (often an interactive shell) with the real and effective user id, group id, and supplemental groups of a given USER. Synopsis: su [ OPTION ]... [ USER [ ARG ]... ] If no USER is given, the default is `root', the super-user. The shell to use is taken from USER's `passwd' entry, or `/bin/sh' if none is specified there. If USER has a password, `su' prompts for the password unless run by a user with effective user id of zero (the super-user). By default, `su' does not change the current directory. It sets the environment variables `HOME' and `SHELL' from the password entry for USER, and if USER is not the super-user, sets `USER' and `LOGNAME' to USER. By default, the shell is not a login shell. Any additional ARGs are passed as additional arguments to the shell. GNU `su' does not treat `/bin/sh' or any other shells specially (e.g., by setting `argv[0]' to `-su', passing `-c' only to certain shells, etc.). `su' can optionally be compiled to use `syslog' to report failed, and optionally successful, `su' attempts. (If the system supports `syslog'.) However, GNU `su' does not check if the user is a member of the `wheel' group; see below. The program accepts the following options. Also see *Note Common options::. `-c COMMAND' `--command=COMMAND' Pass COMMAND, a single command line to run, to the shell with a `-c' option instead of starting an interactive shell. `--fast' Pass the `-f' option to the shell. This probably only makes sense if the shell run is `csh' or `tcsh', for which the `-f' option prevents reading the startup file (`.cshrc'). With Bourne-like shells, the `-f' option disables file name pattern expansion (globbing), which is not likely to be useful. `--login' Make the shell a login shell. This means the following. Unset all environment variables except `TERM', `HOME', and `SHELL' (which are set as described above), and `USER' and `LOGNAME' (which are set, even for the super-user, as described above), and set `PATH' to a compiled-in default value. Change to USER's home directory. Prepend `-' to the shell's name, intended to make it read its login startup file(s). `--preserve-environment' Do not change the environment variables `HOME', `USER', `LOGNAME', or `SHELL'. Run the shell given in the environment variable `SHELL' instead of the shell from USER's passwd entry, unless the user running `su' is not the superuser and USER's shell is restricted. A "restricted shell" is one that is not listed in the file `/etc/shells', or in a compiled-in list if that file does not exist. Parts of what this option does can be overridden by `--login' and `--shell'. `-s SHELL' `--shell=SHELL' Run SHELL instead of the shell from USER's passwd entry, unless the user running `su' is not the superuser and USER's shell is restricted (see `-m' just above). Why GNU `su' does not support the `wheel' group =============================================== (This section is by Richard Stallman.) Sometimes a few of the users try to hold total power over all the rest. For example, in 1984, a few users at the MIT AI lab decided to seize power by changing the operator password on the Twenex system and keeping it secret from everyone else. (I was able to thwart this coup and give power back to the users by patching the kernel, but I wouldn't know how to do that in Unix.) However, occasionally the rulers do tell someone. Under the usual `su' mechanism, once someone learns the root password who sympathizes with the ordinary users, he or she can tell the rest. The "wheel group" feature would make this impossible, and thus cement the power of the rulers. I'm on the side of the masses, not that of the rulers. If you are used to supporting the bosses and sysadmins in whatever they do, you might find this idea strange at first. File: sh-utils.info, Node: Delaying, Next: Index, Prev: Modified command invocation, Up: Top Delaying ******** Perhaps `wait' or other commands should be described here also? * Menu: * sleep invocation:: Delay for a specified time. File: sh-utils.info, Node: sleep invocation, Up: Delaying `sleep': Delay for a specified time =================================== `sleep' pauses for an amount of time specified by the sum of the values of the command line arguments. Synopsis: sleep [ NUMBER[smhd] ]... Each argument is a number followed by an optional unit; the default is seconds. The units are: seconds minutes hours days The only options are `--help' and `--version'. *Note Common options::. File: sh-utils.info, Node: Index, Prev: Delaying, Up: Top Index ***** * Menu: * !: Connectives for test. * !=: String tests. * %: Numeric expressions. * &: Relations for expr. * *: Numeric expressions. * +: Numeric expressions. * -: Numeric expressions. * -: env invocation. * -: su invocation. * -adjustment: nice invocation. * -all: stty invocation. * -all: uname invocation. * -append: tee invocation. * -command: su invocation. * -count: who invocation. * -date: Options for date. * -fast: su invocation. * -file: Options for date. * -group: id invocation. * -groups: id invocation. * -heading: who invocation. * -help: Common options. * -idle: who invocation. * -ignore-environment: env invocation. * -ignore-interrupts: tee invocation. * -login: su invocation. * -machine: uname invocation. * -mesg: who invocation. * -message: who invocation. * -name: id invocation. * -nodename: uname invocation. * -portability: pathchk invocation. * -preserve-environment: su invocation. * -quiet: tty invocation. * -real: id invocation. * -release: uname invocation. * -save: stty invocation. * -set: Options for date. * -shell: su invocation. * -silent: tty invocation. * -sysname: uname invocation. * -universal: Options for date. * -user: id invocation. * -utc: Options for date. * -version: Common options. * -writable: who invocation. * -ADJUSTMENT: nice invocation. * -a: uname invocation. * -a: tee invocation. * -a: Connectives for test. * -a: stty invocation. * -b: File type tests. * -c: File type tests. * -c: su invocation. * -d: Options for date. * -d: File type tests. * -e: File characteristics tests. * -e: echo invocation. * -ef: File characteristics tests. * -eq: Numeric tests. * -f: Options for date. * -f: su invocation. * -f: File type tests. * -g: Access permission tests. * -G: id invocation. * -G: Access permission tests. * -g: id invocation. * -g: stty invocation. * -ge: Numeric tests. * -gt: Numeric tests. * -h: File type tests. * -H: who invocation. * -i: tee invocation. * -i: who invocation. * -i: env invocation. * -k: Access permission tests. * -L: File type tests. * -l: su invocation. * -le: Numeric tests. * -lt: Numeric tests. * -m: su invocation. * -m: who invocation. * -m: uname invocation. * -n: String tests. * -n: echo invocation. * -n: id invocation. * -n: uname invocation. * -n: nice invocation. * -ne: Numeric tests. * -nt: File characteristics tests. * -O: Access permission tests. * -o: Connectives for test. * -ot: File characteristics tests. * -p: su invocation. * -p: File type tests. * -p: pathchk invocation. * -q: who invocation. * -r: id invocation. * -r: Access permission tests. * -r: uname invocation. * -s: File characteristics tests. * -s: who invocation. * -S: File type tests. * -s: uname invocation. * -s: Options for date. * -s: su invocation. * -s: tty invocation. * -t: File type tests. * -T: who invocation. * -u: Options for date. * -u: env invocation. * -u: Access permission tests. * -u: who invocation. * -u: id invocation. * -unset: env invocation. * -v: uname invocation. * -w: who invocation. * -w: Access permission tests. * -x: Access permission tests. * -z: String tests. * .cshrc: su invocation. * /: Numeric expressions. * /bin/sh: su invocation. * /etc/passwd: su invocation. * /etc/shells: su invocation. * /etc/utmp: who invocation. * /etc/utmp: users invocation. * /etc/utmp: logname invocation. * /etc/wtmp: users invocation. * /etc/wtmp: who invocation. * <: Relations for expr. * <=: Relations for expr. * =: String tests. * =: Relations for expr. * ==: Relations for expr. * >: Relations for expr. * >=: Relations for expr. * date options: Options for date. * -su: su invocation. * access permission tests: Access permission tests. * addition: Numeric expressions. * am i: who invocation. * and operator: Connectives for test. * and operator: Relations for expr. * appropriate privileges: hostname invocation. * appropriate privileges: nice invocation. * appropriate privileges: Setting the time. * arbitrary date strings, parsing: Options for date. * arbitrary text, displaying: echo invocation. * arithmetic tests: Numeric tests. * background jobs, stopping at terminal write: Local. * backslash escapes: echo invocation. * basename: basename invocation. * baud rate, setting: Special. * beeping at input buffer full: Input. * beginning of time: Time directives. * block special check: File type tests. * breaks, cause interrupts: Input. * breaks, ignoring: Input. * brkint: Input. * bsN: Output. * bugs, reporting: Introduction. * built-in shell commands, conflicts with: nice invocation. * built-in shell commands, conflicts with: pwd invocation. * built-in shell commands, conflicts with: test invocation. * C-s/C-q flow control: Input. * case translation: Local. * cbreak: Combination. * change or print terminal settings: stty invocation. * character size: Control. * character special check: File type tests. * characters, special: Characters. * check file types: test invocation. * clocal: Control. * cols: Special. * columns: Special. * COLUMNS: Special. * combination settings: Combination. * commands for delaying: Delaying. * commands for exit status: Conditions. * commands for file name manipulation: File name manipulation. * commands for invoking other commands: Modified command invocation. * commands for printing text: Printing text. * commands for printing the working context: Working context information. * commands for printing user information: User information. * commands for redirection: Redirection. * commands for system context: System context. * common options: Common options. * compare values: test invocation. * comparison operators: Relations for expr. * conditions: Conditions. * conflicts with shell built-ins: nice invocation. * conflicts with shell built-ins: pwd invocation. * conflicts with shell built-ins: test invocation. * connectives, logical: Relations for expr. * connectives, logical: Connectives for test. * context, system: System context. * control characters, using ^C: Local. * control settings: Control. * cooked: Combination. * coordinated universal time: Options for date. * crN: Output. * cread: Control. * crt: Combination. * crterase: Local. * crtkill: Local. * crtscts: Control. * csN: Control. * cstopb: Control. * ctlecho: Local. * current working directory, printing: pwd invocation. * date: date invocation. * date directives: Date directives. * date strings, parsing: Options for date. * dec: Combination. * decctlq: Combination. * delay for a specified time: sleep invocation. * delaying commands: Delaying. * destinations, multiple output: tee invocation. * directives, date: Date directives. * directives, literal: Literal directives. * directives, time: Time directives. * directory check: File type tests. * directory components, printing: dirname invocation. * directory, stripping from file names: basename invocation. * dirname: dirname invocation. * disabling special characters: Characters. * displaying text: echo invocation. * division: Numeric expressions. * do nothing, successfully: true invocation. * dsusp: Characters. * echo: Local. * echo: echo invocation. * echoctl: Local. * echoe: Local. * echok: Local. * echoke: Local. * echonl: Local. * echoprt: Local. * effective uid and gid, printing: id invocation. * effective UID, printing: whoami invocation. * eight-bit characters: Combination. * eight-bit characters: Control. * eight-bit input: Input. * ek: Combination. * env: env invocation. * environment variables, printing: printenv invocation. * environment, preserving: su invocation. * environment, printing: env invocation. * environment, running a program in a modified: env invocation. * eof: Characters. * eol: Characters. * eol2: Characters. * epoch, seconds since: Time directives. * equal string check: String tests. * erase: Characters. * evaluation of expressions: expr invocation. * even parity: Control. * evenp: Combination. * examples of date: Examples of date. * examples of expr: Examples of expr. * executable file check: Access permission tests. * existence-of-file check: File characteristics tests. * exit status commands: Conditions. * exit status of expr: expr invocation. * exit status of pathchk: pathchk invocation. * exit status of printenv: printenv invocation. * exit status of true: true invocation. * exit status of true: false invocation. * exit status of tty: tty invocation. * expr: expr invocation. * expression evaluation: test invocation. * expression evaluation: expr invocation. * expressions, numeric: Numeric expressions. * expressions, string: String expressions. * failure exit status: false invocation. * false: false invocation. * fascism: su invocation. * ffN: Output. * fields, padding numeric: date invocation. * file characteristics tests: File characteristics tests. * file name manipulation: File name manipulation. * file name pattern expansion, disabled: su invocation. * file names, checking validity and portability: pathchk invocation. * file names, stripping directory and suffix: basename invocation. * file type tests: File type tests. * flow control, hardware: Control. * flow control, software: Input. * flushing, disabling: Local. * formatting times: date invocation. * getdate.y: Options for date. * globbing, disabled: su invocation. * Greenwich Mean Time: Options for date. * group wheel, not supported: su invocation. * groups: groups invocation. * hangups, immunity to: nohup invocation. * hard link check: File characteristics tests. * hardware flow control: Control. * hardware type: uname invocation. * hat notation for control characters: Local. * help, online: Common options. * history: Introduction. * HOME: su invocation. * hostname: hostname invocation. * hostname: uname invocation. * hup[cl]: Control. * icanon: Local. * icrnl: Input. * id: id invocation. * idle time: who invocation. * iexten: Local. * ignbrk: Input. * igncr: Input. * ignpar: Input. * imaxbel: Input. * immunity to hangups: nohup invocation. * index: String expressions. * information, about current users: who invocation. * inlcr: Input. * inpck: Input. * input settings: Input. * intr: Characters. * introduction: Introduction. * invocation of commands, modified: Modified command invocation. * isig: Local. * ispeed: Special. * istrip: Input. * iuclc: Input. * ixany: Input. * ixoff: Input. * ixon: Input. * kill: Characters. * last DAY: Options for date. * LCASE: Combination. * lcase: Combination. * leading directory components, stripping: basename invocation. * length: String expressions. * line: Special. * line settings of terminal: stty invocation. * LINES: Special. * literal directives: Literal directives. * litout: Combination. * lnext: Characters. * local settings: Local. * logical and operator: Relations for expr. * logical and operator: Connectives for test. * logical connectives: Relations for expr. * logical connectives: Connectives for test. * logical or operator: Relations for expr. * logical or operator: Connectives for test. * login name, printing: logname invocation. * login sessions, printing users with: users invocation. * login shell: su invocation. * login shell, creating: su invocation. * login time: who invocation. * logname: logname invocation. * LOGNAME: su invocation. * lowercase, translating to output: Output. * machine type: uname invocation. * machine-readable stty output: stty invocation. * manipulation of file names: File name manipulation. * match: String expressions. * matching patterns: String expressions. * message status: who invocation. * min: Special. * MIT AI lab: su invocation. * modem control: Control. * modified command invocation: Modified command invocation. * modified environment, running a program in: env invocation. * modifying scheduling priority: nice invocation. * multiplication: Numeric expressions. * name of operating system: uname invocation. * named pipe check: File type tests. * network node name: uname invocation. * newer-than file check: File characteristics tests. * newline echoing after kill: Local. * newline, echoing: Local. * newline, translating to crlf: Output. * newline, translating to return: Input. * next DAY: Options for date. * nice: nice invocation. * nl: Combination. * nlN: Output. * no-op: true invocation. * node name: uname invocation. * noflsh: Local. * nohup: nohup invocation. * nohup.out: nohup invocation. * nohup.out: nohup invocation. * non-directory suffix, stripping: dirname invocation. * nonempty file check: File characteristics tests. * nonzero-length string check: String tests. * not-equal string check: String tests. * numeric expressions: Numeric expressions. * numeric field padding: date invocation. * numeric tests: Numeric tests. * ocrnl: Output. * odd parity: Control. * oddp: Combination. * ofdel: Output. * ofill: Output. * olcuc: Output. * older-than file check: File characteristics tests. * onlcr: Output. * onlret: Output. * onocr: Output. * operating system name: uname invocation. * operating system release: uname invocation. * operating system version: uname invocation. * opost: Output. * options for date: Options for date. * or operator: Relations for expr. * or operator: Connectives for test. * ospeed: Special. * output settings: Output. * owned by effective gid check: Access permission tests. * owned by effective uid check: Access permission tests. * pad character: Output. * pad instead of timing for delaying: Output. * padding of numeric fields: date invocation. * parenb: Control. * parentheses for grouping: expr invocation. * parity: Combination. * parity errors, marking: Input. * parity, ignoring: Input. * parmrk: Input. * parodd: Control. * parsing date strings: Options for date. * pass8: Combination. * passwd entry, and su shell: su invocation. * PATH: env invocation. * PATH: su invocation. * pathchk: pathchk invocation. * pattern matching: String expressions. * permission tests: Access permission tests. * pipe fitting: tee invocation. * portable file names, checking for: pathchk invocation. * POSIX.2: Introduction. * print name of current directory: pwd invocation. * print system information: uname invocation. * print terminal file name: tty invocation. * printenv: printenv invocation. * printf: printf invocation. * printing all or some environment variables: printenv invocation. * printing current user information: who invocation. * printing current usernames: users invocation. * printing groups a user is in: groups invocation. * printing real and effective uid and gid: id invocation. * printing text: echo invocation. * printing text, commands for: Printing text. * printing the current time: date invocation. * printing the effective UID: whoami invocation. * printing the hostname: hostname invocation. * printing user's login name: logname invocation. * priority, modifying: nice invocation. * prterase: Local. * pwd: pwd invocation. * quit: Characters. * raw: Combination. * read from stdin and write to stdout and files: tee invocation. * readable file check: Access permission tests. * real uid and gid, printing: id invocation. * redirection: Redirection. * regular expression matching: String expressions. * regular file check: File type tests. * relations, numeric or string: Relations for expr. * release of operating system: uname invocation. * remainder: Numeric expressions. * remote hostname: who invocation. * repeated output of a string: yes invocation. * restricted shell: su invocation. * return, ignoring: Input. * return, translating to newline: Output. * return, translating to newline: Input. * root, becoming: su invocation. * rows: Special. * rprnt: Characters. * RTS/CTS flow control: Control. * same file check: File characteristics tests. * sane: Combination. * scheduling priority, modifying: nice invocation. * seconds since the epoch: Time directives. * set-group-id check: Access permission tests. * set-user-id check: Access permission tests. * setting the hostname: hostname invocation. * setting the time: Setting the time. * SHELL: su invocation. * shell utilities: Top. * size: Special. * sleep: sleep invocation. * socket check: File type tests. * software flow control: Input. * special characters: Characters. * special settings: Special. * speed: Special. * start: Characters. * sticky bit check: Access permission tests. * stop: Characters. * stop bits: Control. * strftime and date: date invocation. * string expressions: String expressions. * string tests: String tests. * strip directory and suffix from file names: basename invocation. * stripping non-directory suffix: dirname invocation. * stty: stty invocation. * su: su invocation. * substitute user and group ids: su invocation. * substr: String expressions. * subtraction: Numeric expressions. * successful exit: true invocation. * suffix, stripping from file names: basename invocation. * super-user, becoming: su invocation. * supplementary groups, printing: groups invocation. * susp: Characters. * swtch: Characters. * symbolic link check: File type tests. * symbolic links and pwd: pwd invocation. * syslog: su invocation. * system context: System context. * system information, printing: uname invocation. * system name, printing: hostname invocation. * tabN: Output. * tabs: Combination. * tandem: Input. * tee: tee invocation. * TERM: su invocation. * terminal check: File type tests. * terminal file name, printing: tty invocation. * terminal lines, currently used: who invocation. * terminal settings: stty invocation. * test: test invocation. * text, displaying: echo invocation. * time: Special. * time directives: Time directives. * time formats: date invocation. * time setting: Setting the time. * time units: sleep invocation. * time, printing or setting: date invocation. * tomorrow: Options for date. * tostop: Local. * true: true invocation. * tty: tty invocation. * Twenex: su invocation. * two-way parity: Control. * u, and disabling special characters: Characters. * uname: uname invocation. * uppercase, translating to lowercase: Input. * USER: su invocation. * user id, switching: su invocation. * user information, commands for: User information. * user name, printing: logname invocation. * usernames, printing current: users invocation. * users: users invocation. * utilities for shell programming: Top. * utmp: logname invocation. * valid file names, checking for: pathchk invocation. * version number, finding: Common options. * version of operating system: uname invocation. * vtN: Output. * werase: Characters. * wheel group, not supported: su invocation. * who: who invocation. * who am i: who invocation. * whoami: whoami invocation. * working context: Working context information. * working directory, printing: pwd invocation. * writable file check: Access permission tests. * write, allowed: who invocation. * xcase: Local. * XON/XOFF flow control: Input. * yes: yes invocation. * yesterday: Options for date. * zero-length string check: String tests. * \0ooo: printf invocation. * \0xhhh: printf invocation. * \c: printf invocation. * |: Relations for expr. Tag Table: Node: Top Node: Introduction Node: Common options Node: Printing text Node: echo invocation Node: printf invocation Node: yes invocation Node: Conditions Node: false invocation Node: true invocation Node: test invocation 10144 Node: File type tests 11284 Node: Access permission tests 12075 Node: File characteristics tests 12840 Node: String tests 13507 Node: Numeric tests 14089 Node: Connectives for test 14873 Node: expr invocation 15213 Node: Relations for expr 16354 Node: Numeric expressions 17048 Node: String expressions 17646 Node: Examples of expr 19350 Node: Redirection 19932 Node: tee invocation 20373 Node: File name manipulation 21201 Node: basename invocation 21657 Node: dirname invocation 22221 Node: pathchk invocation 22735 Node: Working context information 23898 Node: pwd invocation 24574 Node: stty invocation 25186 Node: Control 27095 Node: Input 27843 Node: Output 29200 Node: Local 30444 Node: Combination 32011 Node: Characters 34149 Node: Special 35689 Node: printenv invocation 37027 Node: tty invocation 37750 Node: User information 38445 Node: id invocation 39105 Node: logname invocation 40248 Node: whoami invocation 40751 Node: groups invocation 41145 Node: users invocation 41791 Node: who invocation 42603 Node: System context 44320 Node: date invocation 44743 Node: Time directives 46107 Node: Date directives 46761 Node: Literal directives 47758 Node: Setting the time 48042 Node: Options for date 49017 Node: Examples of date 50197 Node: uname invocation 51482 Node: hostname invocation 52587 Node: Modified command invocation 53086 Node: env invocation 53653 Node: nice invocation 54916 Node: nohup invocation 56042 Node: su invocation 57165 Node: Delaying 61441 Node: sleep invocation 61698 Node: Index 62230 End Tag Table