See largefile(5) for the description of the behavior of grep when
encountering files greater than or equal to 2 Gbyte ( 2 **31 bytes).
Examples
Example 1: Finding all uses of a word
To find all uses of the word "Posix" (in any case) in the file text.mm,
and write with line numbers:
example% /usr/bin/grep -i -n posix text.mm
Example 2: Finding all empty lines
To find all empty lines in the standard input:
example% /usr/bin/grep ^$
or
example% /usr/bin/grep -v .
Example 3: Finding lines containing strings
Both of the following commands print all lines containing strings abc or def or both:
example% /usr/xpg4/bin/grep -E `abc def'
example% /usr/xpg4/bin/grep -F `abc def'
Example 4: Finding lines with matching strings
Both of the following commands print all lines matching exactly abc or def:
example% /usr/xpg4/bin/grep -E `^abc$ ^def$'
example% /usr/xpg4/bin/grep -F -x `abc def'
Environment Variables
See environ(5) for descriptions of the following environment
variables that affect the execution of grep: LC_COLLATE, LC_CTYPE,
LC_MESSAGES, and NLSPATH.
Exit Status
The following exit values are returned:
0
One or more matches were found.
1
No matches were found.
2
Syntax errors or inaccessible files (even if matches were found).
See Also
egrep(1) , fgrep(1) , sed(1) , sh(1) , attributes(5) , environ(5) ,
largefile(5) , regex(5) , regexp(5) , XPG4(5)
Notes
/usr/bin/grep
Lines are limited only by the size of the available virtual memory.
If there is a line with embedded nulls, grep will only match up to
the first null; if it matches, it will print the entire line.
/usr/xpg4/bin/grep
The results are unspecified if input files contain lines longer than
LINE_MAX bytes or contain binary data. LINE_MAX is defined in
/usr/include/limits.h.