NAME

egrep − search a file for a pattern using full regular expressions

SYNOPSIS

egrep [ −bchilnsv ] [ −e special-expression ] [ −f filename ] [ strings ] [ filename ... ]

AVAILABILITY

SUNWcsu

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.  The file name is printed before each line found if there is more than one input file. 

OPTIONS

−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. 

−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 new-lines.  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. 

−e special-expression
Search for a special expression (full regular expression that begins with a −). 

−f filename
Take the list of full regular expressions from filename.

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). 

NOTES

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 <stdio.h>.

SunOS 5.1/SPARC  —  Last change: 14 Sep 1992