====== AWK - Find and replace a string ======

<code bash>
awk '{gsub(/old_string/, "new_string")};{print}' file.txt
</code>

----

Find either of the old strings and replace with the new string.

<code bash>
awk '{gsub(/old_string1|old_string2|old_string3/, "new_string")};{print}' file.txt
</code>