Grep only last line after find needed files

Question

Hi guys I have an extended question from this thread

I need to find some files given file name and use grep on the last lines of these files to find a certain string.

I currently have:

find my_dir/ -name "*filename*" | xargs grep 'lookingfor'

I'm new to using these commands so much help would be appreciated. Thank you in advance.

score 3 · Accepted Answer · answered Feb 15 '14 at 00:09

3

You can for example do:

find my_dir/ -name "*filename*" -exec sh -c "tail -200 {} | grep lookingfor" \;

setting 200 to the number of last lines you want.

answered Feb 15 '14 at 00:09

fedorqui

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This way he loses names of files – user3159253 Feb 15 '14 at 00:13
@user3159253 He can just add `-H` flag to [tag:grep] to fix that – Reinstate Monica Please Feb 15 '14 at 00:14
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No, he couldn't. tail eats the filename, and grep works just on `STDIN` – user3159253 Feb 15 '14 at 00:36
You actually may try: `tail /path/to/file | grep -H lookingfor` gives me `(standard input):lookingfor` – user3159253 Feb 15 '14 at 00:44
@user3159253 Nice catch, +1 to your answer. – Reinstate Monica Please Feb 15 '14 at 00:56

score 2 · Answer 2 · answered Feb 15 '14 at 00:34

2

I would go with

find  my_dir -name '*filename*' -type f \
     -exec /bin/bash -c '(tail -5 "$1" | grep -q lookingfor) && echo "$1"' _ {} \;

This way you will correctly handle all (well, hopefully all :-)) filenames, even those with " and other strange symbols within. Also I would suggest explicitly call /bin/bash because /bin/sh may be linked on a crippled sh-variant like ash, sash and dash.

answered Feb 15 '14 at 00:34

user3159253

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Also it seems I've just found a bug/a strange behaviour in bash: `bash -c 'echo \$@=\"$@\";' a b c` gives me `$@="b c"` :-). That's why I need an additional `_` between the command argument `{}` – user3159253 Feb 15 '14 at 00:37

score 1 · Answer 3 · answered Feb 15 '14 at 01:15

1

Using find + awk + wc -l

find  my_dir -name '*filename*' -type f -exec awk 'NR>count-100{print FILENAME, $0}' count=$(wc -l < {}) {} +

Adjust 100 to the number of last lines you want.

answered Feb 15 '14 at 01:15

BMW

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Grep only last line after find needed files

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