How do I grep for a string recursively through all .gz
files in all directories and subdirectories?
4 Answers
@Steve Weet is almost there. The use of /dev/null as an additional argument is a nice way to force the filename to be shown (I'll remember that, thanks Steve) but it still runs the exec for every file found -- a huge overhead.
You want to run zgrep as few times as you can, getting the most out of each execution:
find . -iname '*.gz' -print0 | xargs -0 zgrep PATTERN
xargs
will supply as many args (filenames) as possible to zgrep, and repeatedly execute it until it has used all the files supplied by the find
command. Using the -print0
and -0
options allows it to work if there are spaces in any of the file or directory names.
On Mac OS X, you can achieve the same effect without xargs:
find . -iname '*.gz' -exec zgrep PATTERN {} +
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+1 That's really nice. I hadn't realised that xargs passed more than one argument. Much of my *nix command line-fu is 20 years old and I don't think xargs did that 20 years ago. May 24, 2010 at 9:14
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1See my comment to Steve Weet's answer regarding the '+' ending to -exec. Mar 27, 2012 at 15:55
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Use
-H
to always show the file name with the matching line, in GNU grep at least. May 11, 2012 at 7:09
$ zgrep --help
Usage: /bin/zgrep [OPTION]... [-e] PATTERN [FILE]...
Look for instances of PATTERN in the input FILEs, using their
uncompressed contents if they are compressed.
So something like
find . -iname "*.gz" -exec zgrep PATTERN {} \
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The -exec will spawn a new instance of zgrep for every file it iterates over preventing you from seeing the file name. It would be better to use
zgrep -r
to go through a tree or if the -r doesn't work, pipe the output of the find throughxargs zgrep
May 21, 2010 at 10:28 -
I get
/bin/zgrep: -r: option not supported
on my newly installed ubuntu system.– aioobeMay 21, 2010 at 10:31 -
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See my comment to Steve Weet's answer regarding the '+' ending to -exec. Mar 27, 2012 at 15:55
@aioobe is almost there. The command will do the job but won't tell you the file name
The following should tell you the filename as well:
find . -iname "*.gz" -exec zgrep PATTERN {} /dev/null \;
The addition of /dev/null
will ensure that zgrep sees two filenames so it will show you the name of the file if it finds the string
EDIT
Further research reveals that for my machine (OS/X) the -exec
argument to find will add as many filenames as possible (similar to the way xargs
behaves).
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That's pretty cool, I didn't know that about the OSX
-exec
- I'm all about portability so I wouldn't use it in a script, but great for the command prompt.– Stephen PMay 24, 2010 at 15:36 -
For other versions of find, using '+' instead of '\;' to end the exec statement will do the same as OSX, by the stories in this thread, does by default. See the manual entry for '-exec command {} +'. It is not true of all versions of
find
, but most of the modern ones (e.g. in Debian based distros). Mar 27, 2012 at 15:54 -
Use
-H
to always show the file name with the matching line, in GNU grep at least, instead of the/dev/null
hack. May 11, 2012 at 7:10
The following works a treat in zsh
for archive in **/*.gz; do
echo "[${archive}] "
gzip -dc ${archive} | grep -n "String"
done
It may also work in bash
, ksh
, etc...