NOTES
egrep 1 "28 Mar 1995"
egrep - search a file for a pattern using full regular expressions
\f3/usr/bin/egrep\f1
[
-bchilnsv
] [
-e pattern_list
]
[
-f
file
] [
strings
] [
file...
]
\f3/usr/xpg4/bin/egrep\f1
[
-bchilnsvx
]
[
-e pattern_list
]
[
-f
file
] [
strings
] [
file...
]
SUNWcsu
SUNWxcu4
\f3egrep
(\f2expression grep\f1) searches files for a pattern of characters and
prints all lines that contain that pattern.
\f3egrep
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.
If no files are specified,
\f3egrep
assumes standard input.
Normally, each line found is copied to the standard output.
The file name is printed before each line found if there is more than one input file.
\f3/usr/bin/egrep\f1
accepts full regular expressions as described on the
regexp(5)
manual page, except for
\f3\(\f1
and
\f3\)\f1,
and with the addition of:
-
1.
-
A full regular expression followed by
\f3+\f1
that matches one or more occurrences of the full regular
expression.
-
2.
-
A full regular expression followed by
\f3?\f1
that matches 0 or 1 occurrences of the full regular expression.
-
3.
-
Full regular expressions separated by \(bv or
by a
that match strings that are matched by any of the expressions.
-
4.
-
A full regular expression that may be enclosed in parentheses
\f3()\f1
for grouping.
Be careful using the characters
\f3$\f1,
\f3*\f1,
\f3[\f1,
\f3^\f1,
\(bv,
\f3(\f1,
\f3)\f1,
and
\f3\f1
in
\f2full regular expression\f1, because they are
also meaningful to the shell.
It is safest to enclose the entire
full
in single quotes
\f3\(fm\f1...\f3\(fm\f1.
The order of precedence of operators is
\f3[]\f1,
then
\f3\(**?+\f1,
then concatenation, then \(bv and NEWLINE.
/usr/xpg4/bin/egrep
uses the regular expressions described in the
EXTENDED
section of the
regex(5)
manual page.
The following options are supported:
-
-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.
-
-e pattern_list
-
Search for a
pattern_list
(full regular expression
that begins with a
\f3-\f1).
-
-f file
-
Take the list of
full
from
file.
-
-h
-
Suppress printing of filenames when searching multiple files.
-
-i
-
Ignore upper/lower case distinction during comparisons.
-
-l
-
Print the names of files with matching lines once,
separated by NEWLINEs.
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).
-
-s
-
Work silently, that is, display nothing except error messages.
This is useful for checking the error status.
-
-v
-
Print all lines except those that contain the pattern.
-
-x
-
Consider only input lines that use all characters in
the line to match an entire fixed string or
regular expression to be matching lines.
The following operands are supported:
-
file
-
A path name of a file to be searched for the patterns.
If no
file
operands are specified,
the standard input will be used.
-
pattern
-
Specify a pattern to be used during the
search for input.
-
pattern
-
Specify one or more patterns to be used during the
search for input.
This operand is treated as if it were specified as
-e pattern_list\f1.
See
environ(5)
for descriptions of the following environment variables that affect the
execution of
egrep:
LC_COLLATE\f1,
LC_CTYPE\f1,
LC_MESSAGES\f1,
and
NLSPATH\f1.
The following exit values are returned:
-
0
-
if any matches are found
-
1
-
if no matches are found
-
2
-
for syntax errors or inaccessible files
(even if matches were found).
fgrep(1),
grep(1),
sed(1),
sh(1),
environ(5),
regex(5),
regexp(5)
Ideally there should be only one
\f3grep
command, but there is not a single algorithm that spans a wide enough
range of space-time tradeoffs. Lines are limited to
characters;
longer lines are truncated.
is defined in
\f3<stdio.h>.\f1
/usr/xpg4/bin/egrep
is identical to
/usr/xpg4/bin/grep
(see
grep(1)).
Portable applications should use
/usr/xpg4/bin/grep -E.