count number of tab characters in linux

Question

I want to count the numbers of hard tab characters in my documents in unix shell.

How can I do it?

I tried something like

grep -c \t foo

but it gives counts of t in file foo.

Do you want to count the number of tab chars or the number of lines containing tab chars? In the example you gave, if `\t` had worked, you'll get the latter (*number of lines containing tabs*). — Shawn Chin, Jun 14 '12 at 14:43

score 15 · Accepted Answer · answered Jun 14 '12 at 15:02

15

Use tr to discard everything except tabs, and then count:

< input-file tr -dc \\t | wc -c

answered Jun 14 '12 at 15:02

William Pursell

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Wonder who else is here looking to answer this https://cmdchallenge.com/#/find_tabs_in_a_file :) – BenB Feb 04 '17 at 01:27

score 11 · Answer 2 · answered Jun 14 '12 at 15:07

11

Bash uses a $'...' notation for specifying special characters:

grep -c $'\t' foo

answered Jun 14 '12 at 15:07

chepner

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That counts the number of lines with a tab, not the number of tabs. – Gary Oct 26 '22 at 17:40

score 4 · Answer 3 · answered Jun 14 '12 at 14:27

4

Use a perl regex (-P option) to grep tab characters.

So, to count the number of tab characters in a file:

grep -o -P '\t' foo | wc -l

answered Jun 14 '12 at 14:27

dogbane

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-P is GNU only and this post is not tagged Linux. – jordanm Jun 14 '12 at 14:55

score 3 · Answer 4 · answered Jun 14 '12 at 14:29

3

You can insert a literal TAB character between the quotes with Ctrl+V+TAB.

In general you can insert any character at all by prefixing it with Ctrl+V; even control characters such as Enter or Ctrl+C that the shell would otherwise interpret.

answered Jun 14 '12 at 14:29

Joni

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score 1 · Answer 5 · answered Jun 14 '12 at 21:49

1

You can use awk in a tricky way: use tab as the record separator, then the number of tab characters is the total number of records minus 1:

ntabs=$(awk 'BEGIN {RS="\t"} END {print NR-1}' foo)

answered Jun 14 '12 at 21:49

glenn jackman

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And to count the number of tab characters per line : `awk 'BEGIN{FS="\t"}{print NF-1}' foo` (`FS` being `awk`'s field separator). – Skippy le Grand Gourou Oct 23 '15 at 11:38

score 0 · Answer 6 · answered Jun 14 '12 at 14:37

My first thought was to use sed to strip out all non-tab characters, then use wc to count the number of characters left.

< foo.txt sed 's/[^\t]//g' | wc -c

However, this also counts newlines, which sed won't touch because it is line-based. So, let's use tr to translate all the newlines into spaces, so it is one line for sed.

< foo.txt tr '\n' ' ' | sed 's/[^\t]//g' | wc -c

Depending on your shell and implementation of sed, you may have to use a literal tab instead of \t, however, with Bash and GNU sed, the above works.

count number of tab characters in linux

6 Answers6