grep

The grep command is short for globally search for regular expression and print. It is used to search for text or a regular expression in a file or output specified when calling the command.

Example

grep "test" info.log

This will display each line, from the info.log file, that contain the text "test".

x option (-x)

This option will display only lines that have an exact match to a word e.g. "apple" will not get a match on "apples".

v option (-v)

This option will display the inverse results i.e. all the results that do not include the search term.

i option (-i)

This option will make the search case insensitive e.g. "APPLE" will get a match on "apple"

ABC options (-A -B -C)

These options return the lines before and after the line containing the matching search

Examples

grep "test" -A 2 -B 3 info.log

This will return any line containing the text "test" and the 2 lines before it and the 3 lines after it.

grep "test" -C 3 info.log

This will return any line containing the text "test" and the 3 lines before and after it.