tldr/pages/common/grep.md

# grep

> Matches patterns in input text.
> Supports simple patterns and regular expressions.

- Search for an exact string:

`grep {{search_string}} {{file_path}}`

- Search in case-insensitive mode:

`grep -i {{search_string}} {{path/to/file}}`

- Search recursively (ignoring non-text files) in current directory for an exact string:

`grep -rI {{search_string}} .`

- Use extended regular expressions (supporting `?`, `+`, `{}`, `()` and `|`):

`grep -E {{^regex$}} {{path/to/file}}`

- Print 3 lines of context around each match:

`grep -C 3 {{search_string}} {{path/to/file}}`

- Print the count of matches instead of the matching text:

`grep -c {{search_string}} {{path/to/file}}`

- Print line number for each match:

`grep -n {{search_string}} {{path/to/file}}`

- Print file names with matches:

`grep -l {{search_string}} {{path/to/file}}`

- Use the standard input instead of a file:

`cat {{path/to/file}} | grep {{search_string}}`

- Invert match for excluding specific strings:

`grep -v {{search_string}}`
initial commit 2013-12-08 19:56:16 +11:00			`# grep`

Formatted all pages according to guidelines. 2016-01-07 18:31:27 +01:00			`> Matches patterns in input text.`
			`> Supports simple patterns and regular expressions.`
initial commit 2013-12-08 19:56:16 +11:00
Formatted all pages according to guidelines. 2016-01-07 18:31:27 +01:00			`- Search for an exact string:`
Fix lint for common 2015-10-22 15:31:52 +08:00
grep.md: "something" → "search_string"; -r → -rI 2016-06-23 18:50:38 +01:00			`grep {{search_string}} {{file_path}}`
initial commit 2013-12-08 19:56:16 +11:00
various tweaks to grep - use "case-insensitive" in the description of the -i option to make the initialism clear - use path/to/file instead of file_path - mention extended regex syntax and expand first occurrence to spell "regular expression" - clarify wording of the -C example description 2016-04-22 12:24:24 +01:00			`- Search in case-insensitive mode:`
grep: add -i option 2016-01-28 00:12:10 +02:00
grep.md: "something" → "search_string"; -r → -rI 2016-06-23 18:50:38 +01:00			`grep -i {{search_string}} {{path/to/file}}`
grep: add -i option 2016-01-28 00:12:10 +02:00
grep.md: "something" → "search_string"; -r → -rI 2016-06-23 18:50:38 +01:00			`- Search recursively (ignoring non-text files) in current directory for an exact string:`
Add an explanation of recursive search. 2014-01-28 13:41:32 +01:00
grep.md: "something" → "search_string"; -r → -rI 2016-06-23 18:50:38 +01:00			`grep -rI {{search_string}} .`
Add an explanation of recursive search. 2014-01-28 13:41:32 +01:00
Fix extended regular expressions By default, grep already uses regular expressions when searching. The example `grep -e {{^regex$}} {{path/to/file}}` is the same as `grep {{^regex$}} {{path/to/file}}`. However, because of the comment about extended regular expressions, I mistakenly assumed `-e` was the option to enable it. I believe most people would refer to `tldr` in this use case looking for the `-E` extended regular expressions. With this in mind, I believe that example would be better rephrased as this pull request makes it. 2016-07-04 17:40:04 -03:00			- Use extended regular expressions (supporting `?`, `+`, `{}`, `()` and `\|`):
initial commit 2013-12-08 19:56:16 +11:00
Fix extended regular expressions By default, grep already uses regular expressions when searching. The example `grep -e {{^regex$}} {{path/to/file}}` is the same as `grep {{^regex$}} {{path/to/file}}`. However, because of the comment about extended regular expressions, I mistakenly assumed `-e` was the option to enable it. I believe most people would refer to `tldr` in this use case looking for the `-E` extended regular expressions. With this in mind, I believe that example would be better rephrased as this pull request makes it. 2016-07-04 17:40:04 -03:00			`grep -E {{^regex$}} {{path/to/file}}`
initial commit 2013-12-08 19:56:16 +11:00
various tweaks to grep - use "case-insensitive" in the description of the -i option to make the initialism clear - use path/to/file instead of file_path - mention extended regex syntax and expand first occurrence to spell "regular expression" - clarify wording of the -C example description 2016-04-22 12:24:24 +01:00			`- Print 3 lines of context around each match:`
initial commit 2013-12-08 19:56:16 +11:00
grep.md: "something" → "search_string"; -r → -rI 2016-06-23 18:50:38 +01:00			`grep -C 3 {{search_string}} {{path/to/file}}`
initial commit 2013-12-08 19:56:16 +11:00
Formatted all pages according to guidelines. 2016-01-07 18:31:27 +01:00			`- Print the count of matches instead of the matching text:`
initial commit 2013-12-08 19:56:16 +11:00
grep.md: "something" → "search_string"; -r → -rI 2016-06-23 18:50:38 +01:00			`grep -c {{search_string}} {{path/to/file}}`
initial commit 2013-12-08 19:56:16 +11:00
Formatted all pages according to guidelines. 2016-01-07 18:31:27 +01:00			`- Print line number for each match:`
grep: add line number 2016-01-05 00:30:21 -05:00
grep.md: "something" → "search_string"; -r → -rI 2016-06-23 18:50:38 +01:00			`grep -n {{search_string}} {{path/to/file}}`
grep: add line number 2016-01-05 00:30:21 -05:00
grep.md: add -l example (#913) 2016-06-21 15:11:27 +08:00			`- Print file names with matches:`

grep: simplify -l example to match the others 2016-06-24 10:39:17 +01:00			`grep -l {{search_string}} {{path/to/file}}`
grep.md: add -l example (#913) 2016-06-21 15:11:27 +08:00
Formatted all pages according to guidelines. 2016-01-07 18:31:27 +01:00			`- Use the standard input instead of a file:`
initial commit 2013-12-08 19:56:16 +11:00
grep.md: "something" → "search_string"; -r → -rI 2016-06-23 18:50:38 +01:00			`cat {{path/to/file}} \| grep {{search_string}}`
Added invert match parameter. 2014-07-27 10:23:56 +02:00
Formatted all pages according to guidelines. 2016-01-07 18:31:27 +01:00			`- Invert match for excluding specific strings:`
Added invert match parameter. 2014-07-27 10:23:56 +02:00
grep.md: "something" → "search_string"; -r → -rI 2016-06-23 18:50:38 +01:00			`grep -v {{search_string}}`