Question

I have a data file that looks like the following example. I’ve added ‘%’ in lieu of \t, the tab control character.

1234:56%  Alice Worthington
alicew%   Jan 1, 2010 10:20:30 AM%  Closed%   Development
Digg:
Reddit:
Update%%  file-one.txt%   1.1%      c:/foo/bar/quux
Add%%     file-two.txt%   2.5.2%    c:/foo/bar/quux
Remove%%  file-three.txt% 3.4%      c:/bar/quux
Update%%  file-four.txt%  4.6.5.3%  c:/zzz

... many more records of the above form

The records I’m interested in are the lines beginning with “Update”, “Add”, “Remove”, and so on. I won’t know what the lines begin with ahead of time, or how many lines precede them. I do know that they always begin with a string of letters followed by two tabs. So I wrote this regex:

generate-report-for 1234:56 | egrep "^[[:alpha:]]+\t\t.+"

But this matches zero lines. Where did I go wrong?

Edit: I get the same results whether I use '...' or "..." for the egrep expression, so I’m not sure it’s a shell thing.

Answer 1

Apparently \t isn’t a special character for egrep. You can either use grep -P to enable Perl-compatible regex engine, or insert literal tabs with CtrlvCtrli

Even better, you could use the excellent ack