Convert all text file data from
upper to lowercase:
Type the following command at shell:
$ tr
'[:upper:]' '[:lower:]' < input.txt > output.txt
Convert variable data from upper
to lowercase:
$ echo
$VAR_NAME | tr '[:upper:]' '[:lower:]'$ echo $VAR_NAME | tr '[:lower:]'
'[:upper:]'
Recommended readings:
Sample Shell Script
#!/bin/bash
# get filename
echo -n "Enter File Name : "
read fileName
# make sure file exits for reading
if [ ! -f $fileName ]; then
echo "Filename $fileName does not exists"
exit 1
fi
# convert uppercase to lowercase using tr command
tr '[A-Z]' '[a-z]' < $fileName