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====== Grep - Basic usage ======


Assuming a file exists with the following contents:

<file>
boot
book
booze
machine
boots
bungie
bark
aardvark
broken$tuff
robots
</file>

----

===== Simple Search =====

<code bash>
grep "boo" filename
</code>

returns:

<code bash>
boot
book
booze
boots
</code>

<WRAP info>
**NOTE:**  grep prints out every line that contains the word **boo**.
</WRAP>

----

===== Simple Search with Line Numbers =====

<code bash>
grep -n "boo" filename
</code>

returns:

<code bash>
1:boot
2:book
3:booze
5:boots
</code>

<WRAP info>
**NOTE:**  Using the **-n** option prints includes line numbers.
</WRAP>

----

===== Simple Inverse Search with Line Numbers =====

<code bash>
grep -vn "boo" filename
</code>

returns:

<code bash>
4:machine
6:bungie
7:bark
8:aaradvark
9:robots
</code>

<WRAP info>
**NOTE:**  Using the **-v** option prints the inverse of the search string.

This is the items not found.
</WRAP>

----

===== Only determine how many lines contain the Search String =====

<code bash>
grep -c "boo" filename
</code>

returns:

<code bash>
4
</code>

<WRAP info>
**NOTE:**  grep prints out 4 as there are 4 occurrences of the word **boo**.
</WRAP>

----

===== Determine which files contain the Search String =====

<code bash>
grep -l "boo" *
</code>

<WRAP info>
**NOTE:**  The **-l** option prints only the filenames of files in the query that have lines that match the search string.

This is useful if you are searching through multiple files for the same string.
</WRAP>

----

===== Ignore Case =====

<code bash>
grep -i "BOO" filename
</code>

<WRAP info>
**NOTE:**  The **-i** option will treat upper and lower case as equivalent while matching the search string.
</WRAP>

----

===== Exact Matches Only =====

<code bash>
grep -x "boo" filename
</code>

<WRAP info>
**NOTE:**  The **-x** option looks for eXact matches only.

The result in this example will print nothing, because there are no lines that only contain the pattern **boo**.
</WRAP>

----

===== Add additional lines of context =====

<code bash>
grep -A2 "mach" filename
</code>

returns:

<code bash>
machine
boots
bungie
</code>

<WRAP info>
**NOTE:**  The **A** option will print out the search string plus a number of additional lines.

In this example 2 additional lines.
</WRAP>