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Reference Manual
SKSH
A ksh-like Shell for the Amiga
Version 1.2
(Copyright) 1989
Steve Koren
November 19, 1989
Table of Contents
Introduction......................................4
!, !!.............................................5
_ANSI.............................................6
_DIR_.............................................7
_FILE_............................................7
_EXEC_............................................7
alias.............................................8
aliases...........................................9
argcount..........................................10
SKSHINIT..........................................11
sksh..............................................12
basename..........................................13
break.............................................14
builtins..........................................15
cat...............................................16
cd................................................17
chmod.............................................18
clear, cls........................................19
CLINUM............................................20
CMDNUM............................................21
COLUMNS...........................................23
continue..........................................24
cp................................................25
ctpri.............................................26
date..............................................27
dec...............................................28
dir...............................................29
dirname...........................................30
echo..............................................31
exit..............................................32
export............................................33
false.............................................35
for/do/done.......................................36
force.............................................37
function..........................................38
functions.........................................39
getenv............................................40
head..............................................41
history...........................................42
HISTSIZE..........................................43
HOME..............................................44
IFS...............................................46
inc...............................................47
info..............................................48
LINES.............................................49
ll................................................50
local.............................................51
LOGOUT............................................52
ls................................................53
match.............................................55
mem...............................................56
SKSH Amiga Shell Page 2 Reference Manual
mkdir.............................................57
mv................................................58
OLDPWD............................................59
options...........................................60
PATH..............................................63
path..............................................64
PNPC..............................................65
ps................................................66
PS1...............................................67
PS2...............................................68
PWD...............................................69
pwd...............................................70
quit..............................................71
read..............................................72
return............................................73
rm................................................74
rmdir.............................................75
set...............................................76
SHELL.............................................77
shift.............................................78
sleep.............................................79
source............................................80
stack.............................................81
SYSNAME...........................................83
tail..............................................84
time..............................................85
touch.............................................86
true..............................................87
unalias...........................................88
unfunc............................................89
unset.............................................90
variables.........................................91
version...........................................92
wc................................................93
whence............................................94
which.............................................95
while/do/done.....................................96
xd................................................97
SKSH Amiga Shell Page 3 Reference Manual
Introduction
This reference manual describes each SKsh command, variable,
alias, or function in a concise manner. Each page contains
the following information:
Name: The name of the command, alias, etc.
Type: Variable, Alias, Function, Builtin, Keyword, or
External Command.
Default: The default value for variables, or definition for
aliases.
Usage: Command syntax
Range: Legal values for variables or parameters
About: Text describing the command, variable, etc.
Example: A brief example usage.
See Also: Other related commands, variables, etc.
When reading the command syntax, anything in square brackets
is optional. Anything followed by three dots can be
repeated any number of times. A vertical bar is used to
separate option where one or the other, but not both, can be
used.
In general, options to commands are preceded by a dash ('-
'). The dash character passed alone tells a command to stop
reading options. This can be useful to pass a dash as a
parameter. For example,
echo - -
would print a single dash. Also, 'command -a -b' is
equilivant to 'command -ab'
SKSH Amiga Shell Page 4 Reference Manual
_________________________________________________________________
Name: !, !!
Type: Alias
Default: history -e
history -e -1
Usage: ! [ pattern | abs_num | rel_num ]
!!
Range: n/a
About: These two aliases provide an easy way to use the
history -e command. !! will execute the previous
command from the history list by executing history
-e -1. ! will execute a specified command from
the history list. This command can either specify
an absolute number, a relative offset from the
most recent command (the offset should be
negative), or a partial line or pattern to search
for. If a search pattern is given, it should be
enclosed in quotes so that SKsh does not attempt
file name generation on the wildcard pattern.
Example: ! cc
See Also: history
_________________________________________________________________
SKSH Amiga Shell Page 5 Reference Manual
_________________________________________________________________
Name: _ANSI_BS
_ANSI_BE
_ANSI_IS
_ANSI_IE
_ANSI_US
_ANSI_UE
_ANSI_P1
_ANSI_P2
_ANSI_P3
_ANSI_CLEAR
Type: Variable
Default: "^[[1m" (bold-start)
"^[[m" (bold-end)
"^[[3m" (italic-start)
"^[[m" (italic-end)
"^[[4m" (underline-start)
"^[[m" (underline-end)
"^[[0;31;40m" (pen-1)
"^[[0;32;40m" (pen-2)
"^[[0;33;40m" (pen-3)
"^[[H^[[2J" (clear screen)
Usage: $_ANSI_??
Range: n/a
About: These variables are set by SKsh to valid ANSI
escape sequences which control the Amiga console
device. They can be used in echo statements or
prompts.
Since these variables, when output, affect the
console device, they are not normally displayed by
the set command.
Example: echo $_ANSI_CLEAR # clear the screen
See Also: echo
_________________________________________________________________
SKSH Amiga Shell Page 6 Reference Manual
_________________________________________________________________
Name: _DIR_S
_DIR_E
_FILE_S
_FILE_E
_EXEC_S
_EXEC_E
Type: Variable
Default: "$_ANSI_P3" (dir-start)
"$_ANSI_P1" (dir-end)
NULL (file-start)
NULL (file-end)
NULL (exec-start)
NULL (exec-end)
Usage:
Range: n/a
About: These variables control the display format of the
'ls' command when the '-F' option is set (as it is
by default when the 'dir' or 'll' commands are
used). Before printing each file name (whether in
a short or long format listing), SKsh will examine
the file type. If the it is a directory, the
contents of the _DIR_S variable is printed. If it
is a file, the contents if _FILE_S is printed. If
the 'e' bit is set, _EXEC_S is printed. (Because
of this, it is possible to print more than one of
the above variables if the name is both a file and
has its 'e' bit set).
In a similar manner, the contents of the
appropriate _FILE_E, _DIR_E, and _EXEC_E variables
is printed after the file name. This allows the
format of the directory listing to be customized.
These variables are only output when the '-F'
option is used. Also, their contents is printed
verbatim; it is not expanded as with 'PS1'. Thus,
any variables should be expanded when these
variables are set, as in the example below.
Example: _FILE_S="$_ANSI_US" # underline file names
_FILE_E="$_ANSI_UE"
See Also: ls, dir, ll
_________________________________________________________________
SKSH Amiga Shell Page 7 Reference Manual
_________________________________________________________________
Name: alias
Type: Builtin
Default: n/a
Usage: alias [ pattern | string [ '=' ] string ]
Range: n/a
About: The alias builtin command (not to be confused with
'aliases', which is itself an alias) is used to
set and list aliases. If given no parameters, it
simply acts as a 'set -a' command. If given one
parameter, which is a pattern, all aliases
matching that pattern are printed. If given two
parameters (or there where the second is a '='),
the first string becomes an alias with the second
string as its definition.
Aliases are expanded when used as a command. Any
arguments are appended to the text of the aliases
and the resulting string is executed.
Unlike ksh and sh, there can be spaces surrounding
the '=' sign, which is itself optional.
Example: alias foo='echo "This is the foo alias"'
See Also: set, alias, unalias
_________________________________________________________________
SKSH Amiga Shell Page 8 Reference Manual
_________________________________________________________________
Name: aliases
Type: Alias
Default: set -a
Usage: aliases [-s] [pattern]
Range: n/a
About: This alias lists defined aliases. The pattern
uses normal wildcards, but must be quoted to avoid
being interpreted by the filename expansion
mechanism. If the pattern is omitted, all aliases
in the current context are listed except those
beginning with an underscore (hidden aliases).
Only aliases for the current context are listed,
so this command may have a different effect inside
of a subshell or function than when typed
manually.
Example: aliases -s '[a-h]*'
See Also: set, alias
_________________________________________________________________
SKSH Amiga Shell Page 9 Reference Manual
_________________________________________________________________
Name: argcount
Type: Builtin
Default: n/a
Usage: argcount [ parameter ... ]
Range: n/a
About: argcount simply prints a count of its arguments.
Example: argcount should 'print two'
See Also:
_________________________________________________________________
SKSH Amiga Shell Page 10 Reference Manual
_________________________________________________________________
Name: SKSHINIT
Type: Variable
Default: "s:.skshrc"
Usage: $SKSHINIT
Range: n/a
About: This variable is set in the .skshinit file to the
name of a user modifiable configuration file.
Normally this is "s:.skshrc". The user
configuration file is sourced (not executed!) for
interactive SKsh sessions.
The s:.skshrc file is provided for user
modification. Users should not modify
s:.skshinit. If you wish to change something that
is defined in s:.skshinit, simply redefine it in
s:.skshrc. s:.skshrc is sourced after
s:.skshinit.
Your s:.skshrc file may optionally source other
files.
Example:
See Also: sksh, source
_________________________________________________________________
SKSH Amiga Shell Page 11 Reference Manual
_________________________________________________________________
Name: sksh
Type: External Command
Default: n/a
Usage: sksh [ -c string | fspec ... ]
Range: n/a
About: This is, of course, the main SKsh binary. If
invoked with no parameters, an interactive SKsh
session is started. If invoked with the '-c'
option followed by a string, the string is
executed by SKsh as if it had been typed, and SKsh
exits when the operation is complete. If the
string contains spaces, it must be surrounded by
quotes (although this depends on the invoking
shell or environment). If invoked with filespec
arguments, each file in turn is executed (not
sourced). SKsh then exits when finished executing
all the files.
If SKsh is invoked non-interactively, it will
still read the .skshinit file, but not the .skshrc
file. This allows you to have output statements
in the .skshrc file without having this output
appear when non-interacrive scripts are run. If
you really want to run the .skshrc file first,
use:
sksh s:.skshrc my_file.sksh
Example: sksh -c "expr 21 * 2"
See Also: source
_________________________________________________________________
SKSH Amiga Shell Page 12 Reference Manual
_________________________________________________________________
Name: basename
Type: Builtin
Default: n/a
Usage: basename [ fspec ... ]
Range: n/a
About: basename prints the "base" name of a given path.
For example, the basename of sys:System/Format is
simply Format. Note that the basename may be a
directory and not a file; for example, the
basename of sys:usr/bin is bin, even though bin is
a directory. If basename is passed more than one
parameter, it prints the basename of each
parameter in turn.
Example: basename sys:usr/bin/wc
See Also: dirname
_________________________________________________________________
SKSH Amiga Shell Page 13 Reference Manual
_________________________________________________________________
Name: break
Type: Builtin
Default: n/a
Usage: break [ num ]
Range: n/a
About: break exits gracefully from an enclosing for or
while loop. If a numeric argument is given, it
breaks from that many enclosing levels of for or
while.
Example: for a in a b c d e f
do
echo $a
if [ "$a" = "c" ] then break; fi
done
See Also: continue
_________________________________________________________________
SKSH Amiga Shell Page 14 Reference Manual
_________________________________________________________________
Name: builtins
Type: Alias
Default: set -b
Usage: builtins [-s] [pattern]
Range: n/a
About: This aliases lists SKsh builtin commands. The
pattern uses normal wildcards, but must be quoted
to avoid being interpreted by the filename
expansion mechanism. If the pattern is omitted,
all builtins are listed except those beginning
with an underscore character (hidden builtins).
There are currently no hidden builtins.
Example: builtins -s '[a-h]*'
See Also: set
_________________________________________________________________
SKSH Amiga Shell Page 15 Reference Manual
_________________________________________________________________
Name: cat
Type: Builtin
Default: n/a
Usage: cat [ fspec ... ]
Range: n/a
About: cat prints the contents of each file passed to it
on the command line, or the standard input if no
files are passed. The contents of each file are
concatenated, and are not separated by blank
lines.
In SKsh, cat cannot be used to transfer binary
files, only ASCII data. Also, the sequence:
cat my_file.txt > my_file1.txt
can be faster accomplished with the cp command.
Example: cat my_file.txt
See Also: cp
_________________________________________________________________
SKSH Amiga Shell Page 16 Reference Manual
_________________________________________________________________
Name: cd
Type: Builtin
Default: n/a
Usage: cd [ -p | dirname ]
Range: n/a
About: cd changes the current working directory to
dirname, or to the previous directory (the
contents of the OLDPWD variable) if the -p flag is
set. If no parameters are passed, cd moves to the
directory indicated by the HOME variable. This is
convenient when you are doing most of your work in
one place, and wish to return there easily. Under
AmigaDos, the HOME variable can be changed very
easily with:
HOME=.
That is, you do not have to worry about certain
files being in the HOME directory as you do in a
multi-user operating system such as UNIX.
Example: cd -p # go back to old directory
See Also: PWD, pwd, OLDDIR
_________________________________________________________________
SKSH Amiga Shell Page 17 Reference Manual
_________________________________________________________________
Name: chmod
Type: Builtin
Default: n/a
Usage: chmod flags | +flags | -flags [ file ... ]
Range: flags : "hsparewd"
About: chmod changes the file protection bits on the
named files. Flags can be one or more of the
following letters: "hsparewd". If the flags
parameter is given directly with no leading '+' or
'-', the permissions for all the named files are
set to that value. A leading '+' causes the
indicated permissions bits to be set without
changing the others, and a leading '-' causes them
to be reset.
Example: chmod -a *.c # reset archive bit on all .c files
See Also: ls
_________________________________________________________________
SKSH Amiga Shell Page 18 Reference Manual
_________________________________________________________________
Name: clear, cls
Type: Alias
Default: echo -n $_ANSI_CLEAR
Usage: clear
Range: n/a
About: These aliases both clear the screen by echoing
$_ANSI_CLEAR.
Example: clear
See Also: _ANSI_CLEAR
_________________________________________________________________
SKSH Amiga Shell Page 19 Reference Manual
_________________________________________________________________
Name: CLINUM
Type: Variable
Default: n/a
Usage: $CLINUM
Range: 1 to maximum process number limit
About: This variable is set to the CLI process number of
SKsh when it is started.
Example: echo "Process # = $CLINUM"
See Also:
_________________________________________________________________
SKSH Amiga Shell Page 20 Reference Manual
_________________________________________________________________
Name: CMDNUM
Type: Variable
Default: n/a
Usage: $CMDNUM
Range: 1 to 16 million
About: Each time SKsh inputs a line from the keyboard,
this variable is incremented.
Example: echo "$CMDNUM lines have been entered so far."
See Also: history
_________________________________________________________________
SKSH Amiga Shell Page 21 Reference Manual
_________________________________________________________________
Name: cmp
Type: External Command
Default: n/a
Usage: cmp [ -s ] file1 file2
Range: n/a
About: cmp compares two files for equality. It can be
used on binary as well as textual data. cmp is
fast in that if the files are not the same size,
it won't even bother comparing the contents of the
files. cmp normally outputs a message that
indicates whether the files are the same,
different, or one is shorter than the other. If
the -s option is used, compare does not output
this information, but simply returns a zero exit
status if the files were the same, or non-zero if
they were not.
Example: if cmp -s file1 file2
then
echo 'file1 is the same as file2'
else
echo 'file1 is different than file2'
fi
See Also:
_________________________________________________________________
SKSH Amiga Shell Page 22 Reference Manual
_________________________________________________________________
Name: COLUMNS
Type: Variable
Default: 72
Usage: $COLUMNS
Range: 15 to 130
About: This variable is one of several responsible for
controlling the actions of SKsh line editing and
display output. If line editing is enabled, and
the cursor moves beyond the column indicated by
this variable, SKsh slides the line to the left by
12 characters. SKsh also uses this variable to
truncate the output of certain internal SKsh
commands (such as History). This creates a
cleaner display.
This variable is normally set automatically by
SKsh when the window is resized, although this
behavior can be disabled with the options command.
Example: COLUMNS=78
See Also: PNPC, LINES, options
_________________________________________________________________
SKSH Amiga Shell Page 23 Reference Manual
_________________________________________________________________
Name: continue
Type: Builtin
Default: n/a
Usage: continue [ num ]
Range: n/a
About: continue resumes execution with the next iteration
of the surrounding loop, or the nth subsequent
iteration if given a numeric argument.
Example: for a in a b c d e f
do
echo $a
if [ "$a" = "c" ] then continue; fi
echo "This is not echoed when $a = c"
done
See Also: break
_________________________________________________________________
SKSH Amiga Shell Page 24 Reference Manual
_________________________________________________________________
Name: cp
Type: Builtin
Default: n/a
Usage: cp [ -rvc ] source1 [ source2 ... ] destination
Range: n/a
About: cp copies files from one place to another,
optionally renaming them in the process. If the
destination is a directory, the files have the
same name in the destination directory. If more
than one file is copied, the destination must be
either a directory or nonexistant. If it is
nonexistant, it is created as a directory.
The -r flag means do a recursive copy. The -v
flag prints the name of each file as it is copied.
The -c flag causes cp to duplicate file
modification times and protection flags on the
destination files. If you wish to make this the
default behavior, use this alias:
alias cp='force -b cp -c'
Example: cp my_file1 m_file2 my_file3 my_directory
See Also: mv
_________________________________________________________________
SKSH Amiga Shell Page 25 Reference Manual
_________________________________________________________________
Name: ctpri
Type: Alias
Default: ChangeTaskPri
Usage: ctpri
ctpri num
Range: -31 <= num <= 31
About: This alias is provided as a shorter alternative to
the AmigaDos ChangeTaskPri command. Its use is
identical.
Example: ctpri 1
See Also: stack
_________________________________________________________________
SKSH Amiga Shell Page 26 Reference Manual
_________________________________________________________________
Name: date
Type: Builtin
Default: n/a
Usage: date [-aDmdty]
Range: n/a
About: Date prints the current date as a 24 character
string:
DDD mmm dd hh:mm:ss yyyy
Date with the -a (all) option is identical to date
with no parameters, (which prints the date as above).
Date -D prints a three character representation of
the day of the week. Date -m prints a three
character representation of the month. Date -d
prints the day number as two digits. Date -t prints
the time string, and date -y prints the year as four
digits.
Example: date -y # find the year
See Also: time
_________________________________________________________________
SKSH Amiga Shell Page 27 Reference Manual
_________________________________________________________________
Name: dec
Type: Builtin
Default: n/a
Usage: dec var [ count ]
Range: n/a
About: dec decrements the contents of the variable by
count, or 1 if count is not given. It is
equivalent to, but faster than, 'var=$(expr $var -
$count)'
Example: dec my_var 3
See Also: inc
_________________________________________________________________
SKSH Amiga Shell Page 28 Reference Manual
_________________________________________________________________
Name: dir
Type: Alias
Default: ls -bF
Usage: dir [ file | dir ] ...
Range: n/a
About: dir prints a short format directory listing, with
only the basename of each file printed. Note that
the 'F' option to 'ls' is set.
Example: dir s:
See Also: ls, ll
_________________________________________________________________
SKSH Amiga Shell Page 29 Reference Manual
_________________________________________________________________
Name: dirname
Type: Builtin
Default: n/a
Usage: dirname [ fspec ... ]
Range: n/a
About: dirname prints the "directory" name of a given
path. For example, the dirname of
sys:System/Format is simply sys:System. If dirname
is passed more than one parameter, it prints the
dirname of each parameter in turn.
Example: dirname sys:usr/bin/wc
See Also: basename
_________________________________________________________________
SKSH Amiga Shell Page 30 Reference Manual
_________________________________________________________________
Name: echo
Type: Builtin
Default: n/a
Usage: echo [-nc] [ parameter ... ]
Range: n/a
About: The echo command simply prints its arguments to
standard output. If given no arguments, it prints a
newline. Otherwise, it prints its arguments,
separated by a single space, unless the -c option is
set, in which case no separating spaces are printed
(concatenation mode). Echo normally prints a
trailing newline, unless the -n option is set, in
which case no trailing newline is printed.
'echo -c' is useful for concatenating strings:
result = $(echo -c This '+' That)
Example: echo 'These' 'arguments' are "echoed"
See Also:
_________________________________________________________________
SKSH Amiga Shell Page 31 Reference Manual
_________________________________________________________________
Name: exit
Type: Builtin
Default: n/a
Usage: exit [ code ]
Range: n/a
About: exit leaves SKsh, returning execution back to the
invoking shell. If invoked with a numeric
argument, it returns that exit code to the
invoking shell or program.
Note that exit always exits SKsh entirely. To
simply exit a script or function, use the return
statement. If the LOGOUT variable is defined,
exit will execute that string before terminating.
Example: exit # exits successfully
See Also: return, LOGOUT
_________________________________________________________________
SKSH Amiga Shell Page 32 Reference Manual
_________________________________________________________________
Name: export
Type: Builtin
Default: n/a
Usage: export [ var ... ]
Range: n/a
About: export does two things. It sets the value of the
indicated variables in the topmost symbol table in
SKsh, and it sets an AmigaDos environment variable
with the same name and value. This is the only
way to transfer variable values between executions
of SKsh.
Example: export my_var1 my_var2
See Also: getenv
_________________________________________________________________
SKSH Amiga Shell Page 33 Reference Manual
_________________________________________________________________
Name: expr
Type: Keyword
Default: n/a
Usage: expr length string
expr num_expression
expr index str pattern
expr substr num1 num2
Range: n/a
About: expr evaluates and prints the results of an
expression.
expr length string
prints the length in characters of the string
expr num_expression
prints the result of evaluating num_expression.
num_expression is an integer expression
computed with 32 bit integers. '+', '-', '*',
'/', and '%' can be used. '*', '/', and '%'
have a higher precedence than '+' and '-';
otherwise, the expression is evaluated left to
right. Parentheses can be used.
expr index str pattern
prints the index of pattern if found in the
string, or 0 if not found. The first position
in string is 1, not 0. Unlike ksh, pattern can
be more than one character.
expr substr string num1 num2
prints the substring of the string starting at
the position indicated by num1 and extending
for num2 characters. The beginning of the
string is at position one, not 0.
Example: expr 3 * ( 1 + 4 )
See Also:
_________________________________________________________________
SKSH Amiga Shell Page 34 Reference Manual
_________________________________________________________________
Name: false
Type: Builtin
Default: n/a
Usage: false
Range: n/a
About: false simply returns a false exit code, and does
nothing else.
Example: if false
then
echo 'This will never echo'
fi
See Also: true
_________________________________________________________________
SKSH Amiga Shell Page 35 Reference Manual
_________________________________________________________________
Name: for/do/done
Type: Keywords
Default: n/a
Usage: for var in list do stmt_list done
Range: n/a
About: The variable is set to each value in list, and for
each value, the statement list is executed.
Example: for file in *.h *.c
do
cp $file $file.bak
done
See Also: while
_________________________________________________________________
SKSH Amiga Shell Page 36 Reference Manual
_________________________________________________________________
Name: force
Type: Keyword
Default: n/a
Usage: force [ -fba ] command [ parameter ... ]
Range: n/a
About: force forces SKsh to interpret command as a
function, builtin, or alias. Exactly one of the
'f', 'b', and 'a' flags must be present. force is
useful if the builtin commands are redefined.
Example: function date {
echo -n 'The date is: '
force -b date
}
See Also:
_________________________________________________________________
SKSH Amiga Shell Page 37 Reference Manual
_________________________________________________________________
Name: function
Type: Keyword
Default: n/a
Usage: function name { stmt_list }
Range: n/a
About: function defines an SKsh function called name, and
with the definition given by the statement list.
Example: function my_func {
echo "I was passed $# parameters"
See Also: functions
_________________________________________________________________
SKSH Amiga Shell Page 38 Reference Manual
_________________________________________________________________
Name: functions
Type: Alias
Default: set -f
Usage: functions [pattern]
Range: n/a
About: This alias lists defined functions. The pattern
uses normal wildcards, but must be quoted to avoid
being interpreted by the filename expansion
mechanism. If the pattern is omitted, all
functions are listed except those beginning with
an underscore character (hidden functions).
Only functions for the current context are listed,
so this command may have a different effect inside
of a subshell or function than when typed
manually.
Example: functions '[a-h]*'
See Also: set
_________________________________________________________________
SKSH Amiga Shell Page 39 Reference Manual
_________________________________________________________________
Name: getenv
Type: Builtin
Default: n/a
Usage: getenv [ var ... ]
Range: n/a
About: getenv imports the values of the indicated
variable from AmigaDos environment variables with
the same names. This command, coupled with export
command, allows variables to be transferred
between executions of SKsh.
Example: getenv my_var1 my_var2
See Also: export
_________________________________________________________________
SKSH Amiga Shell Page 40 Reference Manual
_________________________________________________________________
Name: head
Type: External Command
Default: n/a
Usage: head [ -num ] [ file ... ]
Range: 0 <= num
About: head prints the first num lines of each named
file, or the standard input if no files are
indicated. If num is not explicitly set, it has a
default value of 10.
Example: head -5 my_file.c my_other_file.c
See Also: tail
_________________________________________________________________
SKSH Amiga Shell Page 41 Reference Manual
_________________________________________________________________
Name: history
Type: Builtin
Default: n/a
Usage: history
history -n
history -e [ pattern | number | offset ]
Range: n/a
About: SKsh maintains the HISTSIZE previous commands in a
list so that they may later be recalled or edited
for re-execution.
history with no parameters simply prints the
history list, with each line prefixed by the
number of the associated command. The -n
parameter leaves out the line numbers.
history -e is used to execute commands from the
history list. If given a positive numeric
argument, it executes the history command at that
number (note that these numbers are derived from
CMDNUM and do not always begin at 1 if CMDNUM >
HISTSIZE). If given a negative numeric argument,
the line executed is the 'nth' before the current;
thus, the example below executes the previous
command. If the argument is a string or pattern,
the most recent command containing that string or
pattern is executed.
Example: history -e -1 # execute previous command
See Also: HISTSIZE, !, !!, CMDNUM, command line editing in
the User's Manual.
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Name: HISTSIZE
Type: Variable
Default: 32
Usage: $HISTSIZE
Range: 0 to 256
About: SKsh keeps a list of the $HISTSIZE most recent
commands available for editing and re-entry.
Example: HISTSIZE=64
See Also: history, options
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Name: HOME
Type: Variable
Default: :
Usage: $HOME
Range: n/a
About: This variable represents the default destination
for the cd command. It can be set to any valid
directory name.
Example: HOME=.
See Also: cd
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Name: if/then/elif/else/fi
Type: Keywords
Default: n/a
Usage: if expr then stmt_list
[ [ elif expr then stmt_list ] ... ]
[ else stmt_list ] fi
Range: n/a
About: If the expression is true (that is, it returns a
zero exit status), then the first statement list
is executed. If any elif statements are present,
each expression is executed, and if it is true,
execution procedes for the associated statement
list. If none of the expressions were true, the
else statement_list is executed.
The expressions can be any command, or a test
expression surrounded by square brackets (see the
user's manual for details).
Example: if [ ! -f name -a ! -d name ]
then
mkdir name
else
echo "$name exists already!"
fi
See Also: while
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Name: IFS
Type: Variable
Default: " \n\t"
Usage: $IFS
Range: n/a
About: Characters in IFS are used to break substituted
text (from variables and command substitution)
into parameters. If IFS is set to the null string
(''), all substituted text will be a single
parameter.
If the 'i' option to SKsh is set (see the options
command), the IFS characters will also be used to
break text from $( ) style command substitution.
Example: [dh0:]: IFS=" \n\t"
[dh0:]: a='Now is the time'
[dh0:]: echo $a
Now is the time
[dh0:]: IFS=''
[dh0:]: echo $a
Now is the time
See Also:
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Name: inc
Type: Builtin
Default: n/a
Usage: inc var [ count ]
Range: n/a
About: inc increments the contents of the variable by
count, or 1 if count is not given. It is
equivalent to, but faster than, 'var=$(expr $var +
$count)'
Example: inc my_var 3
See Also: dec
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Name: info
Type: Builtin
Default: n/a
Usage: info [ device | directory ] ...
Range: n/a
About: info reports the amount of free space available on
a given device or directory. It prints total
space in kilobytes, used space in kilobytes, the
number of bytes per block, the percentage capacity
utilization, the total number of errors, and the
volume name. If info is given a directory name as
an argument, the free space for the directory is
the same as the free space for the device on which
the directory resides.
The SKsh info command reports data in 1024 byte
kilobytes, not 1000 byte kilobytes. This may lead
to a slightly different answer than other info
commands. The SKsh info command will deal
correctly with file systems of up to several
gigabytes (should you happen to have one of
those).
Example: info sys: ram: df0:
See Also:
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Name: LINES
Type: Variable
Default: 24
Usage: $LINES
Range: 3 to anything
About: This variable is currently not used by SKsh; it is
provided for future expansion, and for other
applications or programs which might be
interested.
This variable is automatically set by SKsh when
the window is resized. This behavior can be
turned off with the options command.
Example: if [ $LINES -lt 20 ]
then
echo "We require at least 20 lines!"
fi
See Also: COLUMNS, options
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Name: ll
Type: Alias
Default: ls -lbF
Usage: ll [ file | dir ] ...
Range: n/a
About: ll prints a long format directory listing, with
only the basename of each file printed. Note that
the 'F' option to 'ls' is set.
Example: ll s:
See Also: dir, ls
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Name: local
Type: Builtin
Default: n/a
Usage: local [ varname ... ]
Range: n/a
About: The local command can be used to enforce the
creation of local variables if the 'N' option and
the 'l' to SKsh are set (see the options command).
Normally with the 'N' option set, local variables
are created only if they had not been created
first in an enclosing context. The local command
makes them local even if there had been a
previously defined variable of the same name in an
enclosing context. Note that this command will
have no effect if SKsh local variables are
disabled by turning off the 'l' option.
Example: function my_func {
local answer;
answer = 42
}
See Also: options
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Name: LOGOUT
Type: Variable
Default: 'echo "\nBye!\n"'
Usage: $LOGOUT
Range: n/a
About: This variable is executed by SKsh when the exit
command is used to terminate execution.
Example: LOGOUT=''; # do nothing
See Also: exit
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Name: ls
Type: Builtin
Default: n/a
Usage: ls [ -aldi1bvF ] [ dirname | fname ] ...
Range: n/a
About: This command is used to obtain information about
files or directories. With no arguments, it
simply lists the contents of the current working
directory, leaving out files beginning with a dot.
If the 'I' option to SKsh is set (see the options
command), all .info files are also left out (this
feature exists because I hate .info files).
The 'a' option causes ls to list files beginning
with a dot. Similarly, the 'i' option lists .info
files even if the 'I' option to SKsh is set.
The 'l' option creates a long format list, with
filename, protection status, byte size, block
size, and modification date listed. (The ll
command has been aliased to 'ls -l' to make this
easier).
The '1' option creates a short format list with
one column instead of three (useful for piping
filenames into a command).
The 'd' option forces directories to be printed as
such. Normally if the ls command is given a
directory as an argument, it prints the contents
of that directory. The 'd' option prints
information on the directory itself. This is
useful with the 'l' option to find the
modification date or protection status of a
directory.
The 'b' option causes only the basename of each
file to be printed. Normally, if a path to a file
is given, SKsh will print the path information in
each entry in the ls output. The 'b' option
leaves out the path information, printing only the
basename.
The 'v' option prints a count of entries listed
after the listing itself. Also, a total byte
count is printed, which is the sum of the sizes of
each file listed.
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The 'F' option instructs 'ls' to output the
appropriate _FILE_S, _FILE_E, _DIR_S, _DIR_E,
_EXEC_S, and _EXEC_E variables before and after
each file name printed in either the short or long
directory format. See the documentation on those
variables for details on their usage.
The short form of the ls command normally prints
the files in columns. To decide how many columns
there should be, it examines the $COLUMNS
variable, divides the result by the length of the
longest file name to be printed, and insures at
least a four character gutter between columns.
Example: ls -li my_dir # list my_dir including info files
See Also: options, dir, ll
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Name: match
Type: Builtin
Default: n/a
Usage: match [ -v ] pattern [ string ... ]
Range: n/a
About: match prints each string that matches the pattern
given in the first argument. The pattern is of
the same type used by SKsh for filename wildcards,
but it must be quoted to avoid being expanded in
that manner. If the 'v' flag is set, only strings
not matching the pattern are printed.
Example: match '*.[ch]' file1.foo file1.c file2.h my_file
See Also:
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Name: mem
Type: Builtin
Default: n/a
Usage: mem [ -tcf ]
Range: n/a
About: mem reports the amount of free chip and fast
memory, as well as a total. If the 't' flag is
set, only the total is printed. If the 'c' is
set, only chip memory is listed, and if the 'f'
flag is set, only fast memory is listed.
Example: if [ $(mem -t ] -lt 400000 ]
then
echo 'you must have at least 400K free'
fi
See Also:
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Name: mkdir
Type: Builtin
Default: n/a
Usage: mkdir [ dirname ... ]
Range: n/a
About: mkdir creates directories with names identical to
the parameters passed to it.
Example: mkdir my_dir sys:system/my_other_dir
See Also: rmdir
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Name: mv
Type: Builtin
Default: n/a
Usage: mv [ -v ] source1 [ source2 ... ] destination
Range: n/a
About: mv moves files or directories by renaming them.
Thus, it cannot be used to move data cross
devices. If more than one source is given, the
destination must be a directory or nonexistant.
If it is nonexistant, it is created as a
directory.
The -v option prints the name of each file as it
is moved.
Example: mv my_dir sys:another_dir/my_other_dir
See Also: cp
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Name: OLDPWD
Type: Variable
Default: old present working directory string
Usage: $OLDPWD
Range: n/a
About: When the present working directory is changed,
SKsh puts the old PWD value into OLDPWD. The cd -
p command can be used to return to OLDPWD.
Example: echo $PWD; cd c:; echo $OLDPWD
See Also: PWD, pwd, cd
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Name: options
Type: Builtin
Default: n/a
Usage: options [ -opts | +opts ] ...
Range: n/a
About: The options command provides a way to change the
default behavior of SKsh in a number of areas. If
the command is entered with no parameters, simply
prints the current options string, which is a
series of letters and digits. Otherwise, it
examines each parameter in turn. Each parameter
can begin with a '+' or '-'; a '+' turns "on" the
options corresponding each letter, and a '-' turns
them "off".
+e If set, disable command line editing. This
might be useful for using SKsh from a
terminal that does not support the ANSI
escape sequences SKsh uses for line editing.
Note that is flag is SET in .skshinit. You
must reset it in .skshrc if you wish to use
line editing (the .skshrc file supplied with
SKsh does this).
+f If set, disable wildcard filename expansion.
+h If set, always create a new history line,
even if an old command was executed with
'history -e' or the interactive editing
facility. If not set, executing old lines
will not create a new history entry.
+i If set, use IFS to split $( ) command
substitution text, much as it is used to
split variable value expansion text.
+l If set, variables referenced in functions or
parenthetical subshells will be local
(although this also depends on the 'n'
option). If not set, there will be no local
variables. Note that resetting this flag may
have large side effects when running scripts
and functions. The advantage is that it
takes less memory and is faster.
+n If set, only read scripts, but do not execute
their commands. This is ignored for
SKSH Amiga Shell Page 60 Reference Manual
interactive use.
+p If set, use the exec prompt string mode.
This tells sksh not to use the prompt string
as the prompt directly, but rather to pass it
through the command interpreter first, and
use the results as the prompt. This is
slower, but more powerful.
+s If set, sort filename parameters from
wildcard expansion.
+x If set, print each lines as it is executed.
Moderately useful for debugging scripts.
+E If set, the tab key will expand filenames
like <esc><esc>. This is easier to type, and
closer to the emacs completion mechanism.
(This also requires the 'e' option be reset).
+F If set, map UNIX style filenames to AmigaDos
style file names. A leading '/' becomes a
':', a '~' inserts the contents of the HOME
variable, a '.' becomes the current
directory, and two dots become a slash.
+I If set, leave out the .info files from
directory listings unless the 'i' option to
'ls' is explicitly set.
+N Create new variables in a subshell or
function only if a variable with the same
name does not exist in an outer context. If
one does exist, that one will be used instead
of making a new local variable. This flag
changes the scoping rules, and can have a
large effect in the execution of scripts and
functions; it should be used with care.
+R Disable automatic setting of LINES and
COLUMNS variables. Normally, these variables
are set after the window is re-sized at the
next interactive prompt. To set them
manually and not be overridden by SKsh, use
this options flag.
+S Insert a single blank line before and after
the prompt when typing commands
interactively. For interlace screens where
more than 36 or so lines are displayed, using
the S option can create a more visually
appealing and "tidy" display.
SKSH Amiga Shell Page 61 Reference Manual
Example: # see which options are turned on:
options
# reset all options:
options $(echo -c - '-' $(options))
See Also:
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Name: PATH
Type: Variable
Default: '.,c:'
Usage: $PATH
Range: n/a
About: This variable contains a comma separated list of
directory names. When SKsh executes a file, it
searches for it in these directories. Note that
the current working directory must be specified
explicitly ("."). This lets you change the order
of the search. For example, you could move "." to
the end of the path to search it last. The
directory names in the path do not need to be
terminated by a slash; SKsh will add one if it is
not there.
If SKsh finds the file name in the search path,
and the file has its script bit set, SKsh will
attempt to execute this file as a script instead
of a binary.
The PATH variable is also used by the which and
whence commands.
Example: c:run $(which emacs) my_file
See Also: path, which, whence
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Name: path
Type: Function
Default: see the .skshinit file
Usage: path
path name
path -add [ name ... ]
Range: n/a
About: This function is provided to make the PATH
variable easier to set up and manipulate.
With no arguments, path simply prints the current
path definition.
The second form above sets the path variable to
name.
The third form above adds each name to the path
variable list, provided that it is not there
already. If the name is already a component of
the path, it is ignored.
Example: path -add sys:bin sys:pd/bin
See Also: PATH
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Name: PNPC
Type: Variable
Default: 21
Usage: $PNPC
Range: 0 to 63
About: This variable is one of several responsible for
controlling the actions of SKsh line editing and
display output. PNPC tells SKsh how many non-
printing control characters there are in the
currently defined prompt strings (both PS1 and
PS2). SKsh needs to know this so that it can find
the actual printing width of the prompt string
from the actual character length. You will only
have to change PNPC if you change the number of
ANSI control sequences in your prompt.
Example: PNPC=0
See Also: COLUMNS, PS1, PS2, options
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Name: ps
Type: Builtin
Default: n/a
Usage: ps
Range: n/a
About: ps prints, for each CLI process, the process
number, the address of the process, the priority
of the process, the command name associated with
the process, and the current working directory for
the process.
Example: ps
See Also:
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Name: PS1
Type: Variable
Default: '$_ANSI_P3[$PWD]: $_ANSI_P1'
Usage: $PS1
Range: n/a
About: This variable controls the primary prompt string
displayed by SKsh. If the 'p' SKsh option is not
set (see options), SKsh expands the variables in
the string, and outputs it as the primary prompt.
For this reason, PS1 should be defined to a single
quoted string, so that the variables are expanded
at the proper time and not when PS1 is defined.
If the 'p' option to SKsh is set, SKsh sends the
contents of the PS1 variable through the command
interpreter, and displays the result as the
primary prompt. In this case, PS1 should contain
a string which when executed, will print the
desired prompt. This is slower than the default
method above.
Example: PS1='$ '; PNPC=0
See Also: PS2, PNPC, options
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Name: PS2
Type: Variable
Default: '$_ANSI_P3> $_ANSI_P1'
Usage: $PS2
Range: n/a
About: This variable controls the secondary prompt string
displayed by SKsh. This is the prompt string
displayed when SKsh expects more input, such as
the continuation of a for statement or
unterminated string.
If the 'p' SKsh option is not set (see options),
SKsh expands the variables in the string, and
outputs it as the secondary prompt. For this
reason, PS2 should be defined to a single quoted
string, so that the variables are expanded at the
proper time and not when PS2 is defined.
If the 'p' option to SKsh is set, SKsh sends the
contents of the PS2 variable through the command
interpreter, and displays the result as the
secondary prompt. In this case, PS2 should
contain a string which when executed, will print
the desired prompt. This is slower than the
default method above.
Example: PS2=': '; PNPC=0
See Also: PS1, PNPC, options
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Name: PWD
Type: Variable
Default: present working directory string
Usage: $PWD
Range: n/a
About: SKsh maintains the contents of this variable such
that it always represents the current working
directory.
Example: old_dir="$PWD"; # save old directory
See Also: OLDPWD, pwd, cd
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Name: pwd
Type: Alias
Default: echo "$PWD"
Usage: pwd
Range: n/a
About: This alias simply prints the present working
directory string.
Example: pwd
See Also: PWD, OLDPWD
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Name: quit
Type: Alias
Default: LOGOUT=""; exit
Usage: pwd
Range: n/a
About: quit is like exit but does not execute the value
of the LOGOUT variable first.
Example: pwd
See Also: exit, logout, LOGOUT
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Name: read
Type: Builtin
Default: n/a
Usage: read var
Range: n/a
About: The read command sets the value of the variable by
reading exactly one command from the standard
input. This can be used to accept input from the
keyboard, or it can have its own standard input
redirected to read lines from a file. Read
returns a non-zero return code when it encounters
an end-of-file; this is useful in loops.
Example: while read in_line
do
echo "We read: $in_line"
done < my_input_file.txt
See Also:
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Name: return
Type: Builtin
Default: n/a
Usage: return [ num ]
Range: n/a
About: The return command exits from an enclosing script,
subshell, or function. If given a numeric
argument, it exits from the nth enclosing script,
subshell, or function.
Example: ( echo foo; return; echo 'This is not echoed' )
See Also: continue, break
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Name: rm
Type: Builtin
Default: n/a
Usage: rm [ -rv ] [ file | dir ] ...
Range: n/a
About: This command simply removes the named files. It
will not remove directories unless the '-r' flag
is used; use rmdir to remove a single, empty
directory.
The '-r' flag causes 'rm' to recursively remove
everything under each directory. This is somewhat
dangerous; care should be used.
The '-v' flag prints the name of each file as it
is removed.
Example: rm scrap_file.c
See Also: rmdir
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Name: rmdir
Type: Builtin
Default: n/a
Usage: rmdir [ dir ... ]
Range: n/a
About: This command simply removes the named directories.
It will not remove files or directories which are
not empty.
Example: rmdir scrap_dir
See Also: rmdir
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Name: set
Type: Builtin
Default: n/a
Usage: set [ -fabvs ] [ pattern ... ]
Range: n/a
About: With no options, set lists each variable and its
definition. If pattern arguments, each one is
listed. The 'f' options forces interpretation as
function names, the 'a' option as alias names, the
'b' option as builtin command names, and the 'v'
option as variables names (the default).
The 's' option leaves out the definition, printing
only the name on a single line. In any case,
function definitions are not listed in this
version of SKsh. If the 's' option is used, the
'v' option must explicitly be set to list
variables. Also, more than one of 'f', 'a', 'b',
and 'v' may be set.
SKsh will not list any function, alias, builtin,
or variable whose name begins with an underscore
(hidden variables, etc). This is useful to either
hide definitions from users, or in cases where
printing the contents of a variable would corrupt
the display (such as the _ANSI_CLEAR variable).
The definition of builtin commands is printed as a
short description of the command.
The set command cannot be used to set variables,
as in csh. Use the assignment operator ('=') for
that.
Example: set -b '[a-d]*'
See Also: unset
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Name: SHELL
Type: Variable
Default: sksh
Usage: $SHELL
Range: n/a
About: This variable is set by SKsh to the string "sksh".
It can be used to test which shell is running,
provided that the alternate shell has a similar
syntax.
Example: if [ "$SHELL" != 'sksh' ]
then
echo "This runs only under SKsh!"
fi
See Also: SYSNAME
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Name: shift
Type: Builtin
Default: n/a
Usage: shift [ num ]
Range: n/a
About: This command is used inside of scripts or
functions to shift the parametric arguments. For
example, if $1 = 'foo' and $2 = 'bar', after a
shift, $1 would be 'bar' and $2 would not be set.
The '$#' and '$*' variables are also modified
appropriately. If shift is given a numeric
parameter, it acts as though num consecutive
shifts took place.
Example: function my_func {
echo "$2, $#"
shift
echo "$2, $#"
}
See Also: function
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Name: sleep
Type: Builtin
Default: n/a
Usage: sleep n
Range: n/a
About: Sleep delays execution for n seconds. If n is
omitted, zero, or negative, the command does not
pause. Sleep takes virtually no CPU time. It
will wake up once per second to check for the
break key. Sleep is not guaranteed to be a delay
of exactly n seconds; it may be more on a loaded
system, or if SKsh is preempted by a higher
priority process. It is, however, guaranteed to
be a delay of at least n seconds.
Example: time sleep 5
See Also: time
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Name: source
Type: Builtin
Default: n/a
Usage: source [ file ... ]
Range: n/a
About: This command "sources" the named files; that is,
they are executed, but not in a subshell, so that
any variables, alias, etc, that they define are
really defined in the parent's environment.
A single dot ('.') may be used to source a file as
well; this is compatible with ksh and sh.
A file which is sourced does not have to have its
script bit set (although it won't hurt). However,
a script file which is to be executed by typing
its name must have its script bit set.
Executing a file is equivalent to:
( source file )
Example: source my_init_file.sksh
See Also:
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Name: stack
Type: Function
Default: see the .skshinit file
Usage: stack
stack size
Range: 4000 <= size <= 128000
About: This function is provided to set or examine the stack
size. With no arguments, it prints the current stack
size using c:stack. With one argument, it sets the
stack size to 12000 bytes plus the argument. This is
necessary because SKsh itself requires 12000 bytes of
memory, and executed programs require their stack in
addition to this.
Example: stack 16000
See Also:
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Name: strings
Type: External Command
Default: n/a
Usage: strings [ -num ] [ file ... ]
Range: 0 <= num
About: strings searches the named files for strings of at
least num consecutive printable characters. If
found, it prints them. If num is not set, it
defaults to 6.
Example: strings -10 my_file.o binary_file
See Also:
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Name: SYSNAME
Type: Variable
Default: 'Amiga'
Usage: $SYSNAME
Range: n/a
About: This variable describes the system on which SKsh
is currently being run. There is currently only
one version of SKsh, so this variable will contain
"Amiga". If SKsh is ported to other systems, this
variable can be used to determine the name of the
system.
Example: if [ "$SYSNAME" != 'Amiga' ]
then
echo "This script runs only on Amigas."
fi
See Also: SHELL
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Name: tail
Type: External Command
Default: n/a
Usage: tail [ -num | +num ] [ file ... ]
Range: 0 <= num <= 1024
About: tail prints the last num lines of each named file,
or the standard input if no files are named. If a
'+' precedes num instead of a '-', tail instead
skips num lines and prints the rest of the file.
Since tail uses a temporary ram buffer to store
lines, num is limited to 1024. If num is set to a
larger number, it will be silently truncated to
1024.
Example: tail -15 my_file.c my_other_file.c
See Also: head
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Name: time
Type: Keyword
Default: n/a
Usage: time statement
Range: n/a
About: time executes the statement and prints the
execution time in seconds.
Example: time ( dir; sleep 2 )
See Also:
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Name: touch
Type: Builtin
Default: n/a
Usage: touch [ file ... ]
Range: n/a
About: touch create the named files if they do not exist,
and in any case updates the file modification
timestamp.
Example: touch aaa bbb ccc
See Also:
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Name: true
Type: Builtin
Default: n/a
Usage: true
Range: n/a
About: true simply returns a true exit code, and does
nothing else.
Example: while true
do
echo 'repeat forever!'
sleep 1
done
See Also: false
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Name: unalias
Type: Alias
Default: unset -a
Usage: unalias [ name ... ]
Range: n/a
About: This alias removes existing aliases from the
current context. If no names are given, the
command has no effect. Otherwise, each alias
listed is removed, if it was in fact an alias.
SKsh supplied aliases may be removed, but this is
not recommended.
Example: unalias my_alias my_other_alias
See Also: unset
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Name: unfunc
Type: Alias
Default: unset -f
Usage: unfunc [ name ... ]
Range: n/a
About: This alias removes existing functions from the
current context. If no names are given, the
command has no effect. Otherwise, each function
listed is removed, if it was in fact an function.
SKsh supplied functions may be removed, but this
is not recommended.
Example: function my_function my_other_function
See Also: unset
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Name: unset
Type: Builtin
Default: n/a
Usage: unset [ -fav ] [ name ... ]
Range: n/a
About: This command removes the definition of functions,
aliases, or variables (controlled by the f, a, or
v flags). If no flag is given, the default is to
remove variable definitions.
Example: unset -f my_func1 my_func2
See Also: unfunc, unalias
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Name: variables
Type: Alias
Default: set -v
Usage: variables [-s] [pattern]
Range: n/a
About: This alias lists defined variables. The pattern
uses normal wildcards, but must be quoted to avoid
being interpreted by the filename expansion
mechanism. If the pattern is omitted, all
variables are listed except those beginning with
an underscore character (hidden variables). For
example, _ANSI_P1 is a hidden variable; if it was
printed in the normal variable list, the display
pen would be changed.
Only variables for the current context are listed,
so this command may have a different effect inside
of a subshell or function than when typed
manually.
Example: variables -s '[A-H]*'
See Also: set
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Name: version
Type: Builtin
Default: n/a
Usage: version [ -ds ]
Range: n/a
About: version with no options prints the SKsh version
string and copyright notice. The 'd' option
echoes the compile date of SKsh, and the 's'
option prints a single numeric value that will be
incremented for each release of SKsh. This is
useful in tests, as below.
Example: if [ $(version -s) -lt 3 ]
then
echo 'This script requires a later SKsh
version'
fi
See Also:
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Name: wc
Type: External Command
Default: n/a
Usage: wc [ -hcwlqt ] [ file ... ]
Range: n/a
About: wc is a utility which counts characters, words, or
lines in a given series of files (or the standard
input, if no files are indicated). It normally
produces information on all three counts, preceded
by a title for each column. If the c, w, or l
flags are set, only information on characters,
words, or lines is printed. (These can be
combined; for example 'wc -cl'). If the q flag is
set, wc does its work quietly; that is, it leaves
out titles and file names, only reporting the
actual counts. The t flag can be used to obtain a
total at the end, and the h flag prints a helpful
usage message.
Example: if [ $(wc -lq my_file) -lt 10 ]
then
echo "There must be at least 10 lines"
fi
See Also:
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Name: whence
Type: Builtin
Default: n/a
Usage: whence [ name ... ]
Range: n/a
About: whence reports how each name would be interpreted
if it was used as a command. It will report
whether the name will be interpreted as a builtin
command, an alias, a function, or an external
statement. If the command is interpreted as an
external statement, a path to the command is
printed.
Example: whence whence if path ll
See Also: which
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Name: which
Type: Builtin
Default: n/a
Usage: which [ -s ] [ name ... ]
Range: n/a
About: which searches the current PATH variable for an
occurrence of name. If it finds one, the path to
name is printed. Multiple names are accepted, in
which case the process is repeated for each one.
If the '-s' option is set, which will terminate
silently if the name is not found in the search
path. Normally it prints a message to that
effect.
Although which does not know about aliases or
functions as whence does, it is often more useful
in scripts or from the command line. For example,
if you know that "my_file" is in the search path,
you can say:
ll $(which -s my_file)
to print information on my_file without knowing
where it is. The example below is another
possible use. In the function, which is used both
to avoid interpreting "run" recursively as a
function, and to find the desired binary. A
better form of the 'run' function is included with
the default '.skshinit' file.
Example: function run {
cmd="$1"
shift
$(which -s run) $(which $cmd) $*
}
See Also: whence
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Name: while/do/done
Type: Keywords
Default: n/a
Usage: while expr do stmt_list done
Range: n/a
About: The statement list is executed while the
expression is true (returns a zero exit status).
Example: a=1
while [ $a -le 10 ]
do
echo "a = $a"
done
See Also: for
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Name: xd
Type: External Command
Default: n/a
Usage: xd [ file ... ]
Range: n/a
About: xd (hex dump) prints a hexadecimal dump of each
named file, or the standard input if no files are
named. It prints the hex address of the current
offset as 8 digits, then a hex dump of 16 bytes
separated into groups of 2 bytes, then an ASCII
representation of the 16 bytes, or '.' if the byte
is not a printable character.
Example: xd any_old_file
See Also:
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