Sample script is shown below:
#!/bin/bash
sed -i~ 's/user1/user2/g' myfile.txt
It replaces user1 with user2 in myfile.txt
How can I change above script to get confirmation that the script found user1 & replaced it with user2?
Basically, if it doesn't find user1, it should give an alert message on the command prompt.
Thanks!
An alternative to diffing after is to grep before:
grep -q 'user1' myfile.txt && sed -i~ 's/user1/user2/g' myfile.txt || echo "user1 not there"
The -q means that grep runs quietly and returns success if found, so then and only then will it go on to do the replacement.
Try diff tool:
fgrep -q 'user1' myfile.txt 2>&1 1>/dev/null
if [ "$?" -eq 0 ]; then
echo " user1 found."
fi
...
diff -q myfile.txt myfile.txt~ 2>&1 1>/dev/null
if [ "$?" -eq 1 ]; then
echo " Match found & Replaced."
fi
sedtouch a flag file if it does a successful substitution. As an optimization, only do it for the first match. If your input files are too large for the grep && sed and diff solutions, it might be worth piecing together a somewhat more complex sed script.