Finding all files containing a word and then counting the number of lines

Question

I need to recursively find all files that contain a specific word and if the word exists in file I need to find out the number of lines in that file. I have been trying to use grep but I have been not successful so far.

Answer 1

grep -Zlr "\<THE_WORD\>" * | xargs -0 wc -l

Options for grep:

• -Z - end printed filenames with a zero/null byte to delimit them (helps with weird filenames, or those with spaces)
• -l - list names of files, not the lines that match
• -r - recursively
• -i - ignore case (optional, but probably useful to find ALL the variants)

And in the quotes, around THE_WORD, I've used 'word delimiters' (\< and \>), which prevent 'HI' from being found in 'WHICH'. Useful, that.

Pipe the zero delimited list of filenames containing "THE_WORD" to xargs, telling it to expect zero byte delimiters (-0), execute wc (word-count), showing line counts (-l)

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EDIT:

To answer your query in the comments, try this variation: (I've done some research!)

grep -oi "\<THE_WORD\>" /dev/null * | sort | uniq -c 

And explanation:

• -o says to output EVERY occurrence on the line, so if you have "blah blah THE_WORD blah THE_WORD blah blah", it'll output TWICE for that LINE, without this flag, grep would only output ONCE for this line.
• -i match upper & lowercase variations (ie, The_Word, the_word, etc)
• \< must be a start of a word, thus 'HI' is NOT found in 'WHICH'.
• `>' must end on end of a word, again preventing 'HI' being found in 'WHICH'

• /dev/null a dummy filename to force grep to ALWAYS output filenames, even if you only search one file. This CAN be forced by using the -H option for grep, but I find this just as easy and more descriptive since -H could be rated as 'little-known-magic'

• pipe all that to sort (which, uh.... sorts...)

• pipe the sorted list to uniq, with -c to count each occurrence in the sorted list

And taadaa!!

An example:

File example.c contains:

(*H)->segments=realloc((*H)->segments,sizeof(segment_t*)*((*H)->segment_count+1));

xenon-lornix:~/projects/emma> grep -oi "\<H\>" /dev/null *.c | sort | uniq -c
  3 example.c:H

Thus returning a list of a count (3), where (example.c), and what (H)!! Voila!! Yaaayy!!

Another, with same file contents:

xenon-lornix:~/projects/emma> grep -oi "\<segments\>" /dev/null example.c | sort | uniq -c
  2 aa.c:segments

You can see here it found both segments, but didn't count segment. The \< & \> force matching only entire words. THE_WORD123 does NOT match _THE_WORD_, word breaks are at non-alpha-numeric characters. FYI.