grep -h july *
sed s/apple/(&)/ < filename
echo “unix is good” | rev | cut -f1 -d’ ‘ | rev
When you use a single file as input to the grep command to search for a pattern, it won’t print the filename in the output. Now write a grep command to print the filename in the output without using the ‘-H’ option.
grep pattern filename /dev/null The /dev/null or null device is special file that discards the data written to it. So, the /dev/null is always an empty file. Another way to print the filename is using the ‘-H’ option. The grep command for this is grep -H pattern filename