====== Grep ======
I don't make great use of all the gnu tools, but they sure come in handy some times.

===== Use =====

Basic use is searching a file for a particular term, and grep spitting out each line that term occurs in.

<code bash>grep [term] [file]</code>

Search all files in current folder for a term.

<code bash>grep -r -n -i [term] .</code>

With the ''E'' flag you can use the usual [[regular_expression|regular expressions]]. So searching for either of two terms:

<code bash>grep -E '[term1]|[term2]' [file]</code>

Otherwise there's also a utility called egrep.

NB: ''[file]]'' doesn't even have to be a file, you can use wildcards and things there too.

There's probably a better way to do this, but to search for instances with all terms I use a pipe, like:

<code bash>grep '[term1]' [file] | grep '[term2]'</code>

===== See Also =====
  * [[https://www.gnu.org/software/grep/manual/html_node/index.html|GNU Grep 3.4]] on gnu.org
  * [[wp>Grep]]
  * [[github>phiresky/ripgrep-all]] - Searches more file kinds.
  * [[https://sourceforge.net/projects/multiline-grep/|Multiline Grep]]
  * [[plaintext]]

{{tag>cli guide linux plaintext software tool unix}}