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--- bash:strings:find_replace [2021/01/13 21:58] – created peter
+++ bash:strings:find_replace [2021/02/10 16:04] (current) – peter
@@ Line 1: / Line 1: @@
 ====== 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>