+.TH GREP 1 11/16/79
+.UC
+.SH NAME
+grep, egrep, fgrep \- search a file for a pattern
+.SH SYNOPSIS
+.B grep
+[ option ] ...
+expression [ file ] ...
+.LP
+.B egrep
+[ option ] ...
+[ expression ]
+[ file ] ...
+.PP
+.B fgrep
+[ option ] ...
+[ strings ]
+[ file ]
+.SH DESCRIPTION
+Commands of the
+.I grep
+family search the input
+.I files
+(standard input default)
+for lines matching
+a pattern.
+Normally, each line found
+is copied to the standard output.
+.I Grep
+patterns are limited regular expressions in the style of
+.IR ex (1);
+it uses a compact nondeterministic algorithm.
+.I Egrep
+patterns are full regular expressions;
+it uses a fast deterministic algorithm that
+sometimes needs exponential space.
+.I Fgrep
+patterns are fixed strings; it is fast and compact.
+The following options are recognized.
+.TP
+.B \-v
+All lines but those matching
+are printed.
+.TP
+.B \-x
+(Exact) only lines matched in their entirety are printed
+.RI ( fgrep
+only).
+.TP
+.B \-c
+Only a count of matching lines is printed.
+.TP
+.B \-l
+The names of files with matching lines are listed (once)
+separated by newlines.
+.TP
+.B \-n
+Each line is preceded by
+its relative line number in the file.
+.TP
+.B \-b
+Each line is preceded by the block number
+on which it was found.
+This is sometimes useful in locating
+disk block numbers by context.
+.TP
+.B \-i
+The case of letters is ignored in making comparisons.
+(E.g. upper and lower case are considered identical.)
+(\fIgrep\fR\| only)
+.TP
+.B \-s
+Silent mode.
+Nothing is printed (except error messages).
+This is useful for checking the error status.
+.TP
+.B \-w
+The expression is searched for as a word
+(as if surrounded by `\e<' and `\e>', see
+.IR ex (1).)
+(\fIgrep\fR\| only)
+.TP
+.BI \-e " expression"
+Same as a simple
+.I expression
+argument,
+but useful when the
+.I expression
+begins with a \-.
+.TP
+.BI \-f " file"
+The regular expression
+.RI ( egrep )
+or string list
+.RI ( fgrep )
+is taken from the
+.I file.
+.PP
+In all cases the file name is shown if there is more than one input file.
+Care should be taken when
+using the characters
+$ * [ ^ | ( ) and \\ in the
+.I expression
+as they are
+also meaningful to the Shell.
+It is safest to enclose the
+entire
+.I expression
+argument in single quotes \' \'.
+.PP
+.I Fgrep
+searches for lines that contain one of the (newline-separated)
+.I strings.
+.PP
+.I Egrep
+accepts extended regular expressions.
+In the following description `character' excludes
+newline:
+.IP
+A \e followed by a single character
+other than newline
+matches that character.
+.IP
+The character ^ ($) matches the beginning (end) of
+a line.
+.IP
+A
+.B .
+matches any character.
+.IP
+A single character not otherwise endowed with special
+meaning matches that character.
+.IP
+A string enclosed in brackets [\|]
+matches any single character from the string.
+Ranges of ASCII character codes may be abbreviated
+as in `a\-z0\-9'.
+A ]
+may occur only as the first character of the string.
+A literal \- must be placed where it can't be
+mistaken as a range indicator.
+.IP
+A regular expression followed by * (+, ?) matches a sequence
+of 0 or more (1 or more, 0 or 1)
+matches of the regular expression.
+.IP
+Two regular expressions concatenated
+match a match of the first followed by a match of
+the second.
+.IP
+Two regular expressions separated by | or newline
+match either a match for the first or a match for the
+second.
+.IP
+A regular expression enclosed in parentheses
+matches a match for the regular expression.
+.LP
+The order of precedence of operators
+at the same parenthesis level
+is [\|] then
+*+? then concatenation then | and newline.
+.SH "SEE ALSO"
+ex(1),
+sed(1),
+sh(1)
+.SH DIAGNOSTICS
+Exit status is 0 if any matches are found,
+1 if none, 2 for syntax errors or inaccessible files.
+.SH BUGS
+Ideally there should be only one
+.I grep,
+but we don't know a single algorithm that spans a wide enough
+range of space-time tradeoffs.
+.PP
+Lines
+are limited to 256 characters;
+longer lines are truncated.
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