How can I filter/grep some output only by certain column?

Question

How can I filter some output only by certain column?

I need something like this:

tail -f logs/access_log | grep -v "200" --only-in-column=1

So I want to see only lines that don't have string '200' in first column.

OS: Linux

Answer 1

awk is probably the canonical tool for this kind of problem.

$ cat data
foo 200 bar
foo 200 baz
bar 4   baz

$ cat data | awk '$2 != 200 { print $0 }'
bar 4   baz

Answer 2

This will work:

tail -f logs/access_log | grep -v '^200[[:blank:]]'

which excludes lines that begin with "200" followed by a space or a tab.

You can choose different delimiter sets depending on your needs.

tail -f logs/access_log | grep -v '^200[^[:alnum:]]'

which excludes lines that begin with "200" followed by any character other than alphabetic or numeric characters.