Searching tabs in a list of files

Sometimes you want to find files with tabs (\t) within their content. With most greps this is a difficult task:

$ bash
$ TAB=$(printf "\t")
$ grep -Hn "$TAB" *
[download]

Using perl, there is another problem: If you want to see the line number, you usually use the special $. variable. But:

Because <> never does an explicit close, line numbers increase across ARGV files.

So you have to close ARGV manually:

$ perl -lne 'print "$ARGV:$.:$_" if /\t/ } continue { close ARGV if eo
+f } {' *
[download]

-- Frank

Comment on Searching tabs in a list of files Select or Download Code

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Re: Searching tabs in a list of files by davidrw (Prior) on Aug 25, 2005 at 12:42 UTC
I've never had occaison to run into that behavior -- very handy thing to be aware of though! I just had a few TMTOWTDI comments: This is still easy with `grep` if you know how to generate the tab character: `grep -Hn '<TAB>' ` [download] Where "<TAB>" represents a tab character. To type the tab, first hit ctrl-v, then hit TAB -- that should insert an actual tab character. (note it probably won't copy/paste correctly, so be careful if you're copying the grep command from a notes file or something) Also, `cat` can be useful here as well (-n shows line numbers, -T shows TABs as "^I"): `cat -nT /tmp/foo \| grep '\^I'` [download] Couple alternative perl ways: `perl -lne 'print "$ARGV:$.:$_" if /\t/; close ARGV if eof' ` [download] Identical to yours except i believe that the `... } continue { ... } {` construct is unnecessary here and confusing at first glance until the reader remembers (if they know) that this is inserted (because of the -n) in a `while (<>) { ... }` loop. Since the original problem is that the line numbers increase accross ARGV files, this, while simple, isn't sufficient (works for only a single file) ... `perl -ne 'print "$ARGV:$.:$_" if /\t/' /tmp/foo` [download] ... so Yet Another Alternative :) would be to just wrap that in a shell (e.g. bash here) loop: `for f in * ; do perl -ne 'print "$ARGV:$.:$_" if /\t/' $f; done` [download] (more awkward/more steps, but potentially useful in certains cases)	[reply] [d/l] [select]
Re: Searching tabs in a list of files by ambrus (Abbot) on Aug 26, 2005 at 09:15 UTC
As a bash extension, you can do this: `grep $'\t' ` Also, you can put a literal tab between quotes to the command (in a script, I did that with a literal \x1b once); in the interactive command line, you can insert a tab with c-Vc-I. However, I have my cgrep: Egrep clone with function name display installed on my system, so I can just type `cgrep '\t' `.	[reply] [d/l] [select]


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