Sed command can be used to perform search and replace keywords in Linux. But its case sensitive by default.
We need to add options to make it case insensitive.
Let us see the example queries.
#sed -e 's/word1/word1/gI' file.txt
The above command will perform case insensitive search and replace. We need to replace word1, word2 and file.txt with the corresponding values.
If the system having an older version of sed, we need to use an alternative.
#sed 's/[wW][oO][rR][dD]1/word2/g' file.txt
We need to replace word1, word2 and file.txt with the corresponding values.