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====== BASH - Strings - Find & Replace ======

<code bash>
var="abcdabe"

echo ${var/ab/fg}
</code>

returns:

<code bash>
fgcdabe
</code>

<WRAP info>
**NOTE:**  Only the first match is changed.

To change all occurrences use:

<code bash>
var="abcdabe"

echo ${var//ab/fg}
</code>

returns:

<code bash>
fgcdfge
</code>

</WRAP>

----

===== Changing contents within a file =====

<code bash>
contents=$(< infile.txt)
$ echo "${contents/$old/$new}"
</code>

<WRAP info>
**NOTE:**  This reads the file into a Bash variable and uses parameter expansion.

  * **infile.txt**:  The input file here is named **infile.txt**.
  * **$old**:  The string to replace.
  * **$new**:  The replacement string.
</WRAP>

----

To change the file in-place:

<code bash>
echo "${contents/$old/$new}" > infile.tmp && mv infile.tmp infile.txt
</code>