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1993-01-04
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grep searches a file for a given pattern. Execute by
grep [flags] regular_expression file_list
Flags are single characters preceeded by '-':
-c Only a count of matching lines is printed
-f Print file name for matching lines switch, see below
-n Each line is preceeded by its line number
-v Only print non-matching lines
The file_list is a list of files (wildcards are acceptable on RSX modes).
The file name is normally printed if there is a file given.
The -f flag reverses this action (print name no file, not if more).
The regular_expression defines the pattern to search for. Upper- and
lower-case are always ignored. Blank lines never match. The expression
should be quoted to prevent file-name translation.
x An ordinary character (not mentioned below) matches that character.
'\' The backslash quotes any character. "\$" matches a dollar-sign.
'^' A circumflex at the beginning of an expression matches the
beginning of a line.
'$' A dollar-sign at the end of an expression matches the end of a line.
'.' A period matches any character except "new-line".
':a' A colon matches a class of characters described by the following
':d' character. ":a" matches any alphabetic, ":d" matches digits,
':n' ":n" matches alphanumerics, ": " matches spaces, tabs, and
': ' other control characters, such as new-line.
'*' An expression followed by an asterisk matches zero or more
occurrances of that expression: "fo*" matches "f", "fo"
"foo", etc.
'+' An expression followed by a plus sign matches one or more
occurrances of that expression: "fo+" matches "fo", etc.
'-' An expression followed by a minus sign optionally matches
the expression.
'[]' A string enclosed in square brackets matches any character in
that string, but no others. If the first character in the
string is a circumflex, the expression matches any character
except "new-line" and the characters in the string. For
example, "[xyz]" matches "xx" and "zyx", while "[^xyz]"
matches "abc" but not "axb". A range of characters may be
specified by two characters separated by "-". Note that,
[a-z] matches alphabetics, while [z-a] never matches.
The concatenation of regular expressions is a regular expression.