Issue
I have a file that looks like this:
1 2HE MET 1.8493
1 3HE MET 1.3568
2 H GLN 6.1731
2 HA GLN 4.2384
2 2HB GLN 2.2204
2 3HB GLN 1.3062
I use the grep command: grep H file and get all the lines as shown above. I would like to only retrieve the line 2 H GLN 6.1731.
I've used grep 'H$'file as well as grep -x H processed_shifts.out but do not get any output with these commands. How could I modify the grep command to only get line 3 as the output?
Solution
If you're using GNU grep then you can use the -w or --word-regexp flag, or wrap the regex with word boundaries:
grep '\bH\b'
However, this will be non-portable, since POSIX grep lacks the -w flag and neither basic nor extended regular expressions support word boundaries. So if you wish for the command to be portable then you'll have to do something like
grep ' H '
or otherwise use a more powerful language, like AWK:
awk '$2=="H" { print }'
Answered By - Connor Smith Answer Checked By - Pedro (WPSolving Volunteer)