EGREP(1) (Directory and File Management Utilities) EGREP(1)
NAME
egrep - search a file for a pattern using full regular
expressions
SYNOPSIS
egrep [options] full regular expression [file ...]
DESCRIPTION
egrep (expression grep) searches files for a pattern of
characters and prints all lines that contain that pattern.
egrep uses full regular expressions (expressions that have
string values that use the full set of alphanumeric and
special characters) to match the patterns. It uses a fast
deterministic algorithm that sometimes needs exponential
space.
egrep accepts full regular expressions as in ed(1), except
for \( and \), with the addition of:
1. A full regular expression followed by + that matches
one or more occurrences of the full regular
expression.
2. A full regular expression followed by ? that matches 0
or 1 occurrences of the full regular expression.
3. Full regular expressions separated by | or by a new-
line that match strings that are matched by any of the
expressions.
4. A full regular expression that may be enclosed in
parentheses () for grouping.
Be careful using the characters $, *, [, ^, |, (, ), and \
in full regular expression, because they are also meaningful
to the shell. It is safest to enclose the entire full
regular expression in single quotes '...'.
The order of precedence of operators is [], then *?+, then
concatenation, then | and new-line.
If no files are specified, egrep assumes standard input.
Normally, each line found is copied to the standard output.
Page 1 May 1989
EGREP(1) (Directory and File Management Utilities) EGREP(1)
The file name is printed before each line found if there is
more than one input file.
Command line options are:
-b Precede each line by the block number on which it was
found. This can be useful in locating block numbers
by context (first block is 0).
-c Print only a count of the lines that contain the
pattern.
-i Ignore upper/lower case distinction during
comparisons.
-l Print the names of files with matching lines once,
separated by new-lines. It does not repeat the names
of files when the pattern is found more than once.
-n Precede each line by its line number in the file
(first line is 1).
-v Print all lines except those that contain the pattern.
-e special_expression
Search for a special expression (full regular
expression that begins with a -).
-f file
Take the list of full regular expressions from file.
SEE ALSO
ed(1), fgrep(1), grep(1), sed(1), sh(1).
DIAGNOSTICS
Exit status is 0 if any matches are found, 1 if none, 2 for
syntax errors or inaccessible files (even if matches were
found).
BUGS
Ideally there should be only one grep command, but there is
not a single algorithm that spans a wide enough range of
space-time tradeoffs. Lines are limited to BUFSIZ
characters; longer lines are truncated. BUFSIZ is defined
in /usr/include/stdio.h.
Page 2 May 1989