How to find first match in multiple files

command linefindgrep

Is there a way for the find command to search for the first match or occurrence of a string or pattern within each of multiple files? I've been using the usual syntax:

 find dir -iname '*.ext' -exec command 'pattern' {} \;

(I also happen to be searching pdfs with -exec pdfgrep but suppose that would be a special case of the general problem and may be dealt with afterwards or separately.)

Keep in mind this is not same as the commonly-asked problem of producing the first result from a search using find with -quit or head -n 1.

Best Answer

Just use the -m option of GNU grep which stops reading the file after (in the example) one match.

find dir -iname '*.ext' -exec grep -m 1  'pattern' {} \;

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Find Command – How to Stop After First Match

With GNU or FreeBSD find, you can use the -quit predicate:

find . ... -print -quit

The NetBSD find equivalent:

find . ... -print -exit

If all you do is printing the name, and assuming the filenames don't contain newline characters, you could do:

find . ... -print | head -n 1

That will not stop find after the first match, but possibly, depending on timing and buffering upon the second match or (much) later. Basically, find will be terminated with a SIGPIPE when it tries to output something while head is already gone because it has already read and displayed the first line of input.

Note that not all shells will wait for that find command after head has returned. The Bourne shell and AT&T implementations of ksh (when non-interactive) and yash (only if that pipeline is the last command in a script) would not, leaving it running in background. If you'd rather see that behaviour in any shell, you could always change the above to:

(find . ... -print &) | head -n 1

If you're doing more than printing the paths of the found files, you could try this approach:

find . ... -exec sh -c 'printf "%s\n" "$1"; kill "$PPID"' sh {} \;

(replace printf with whatever you would be doing with that file).

That has the side effect of find returning an exit status reflecting the fact that it was killed though.

Actually, using the SIGPIPE signal instead of SIGTERM (kill -s PIPE instead of kill) will cause some shells to be more silent about that death (but would still return a non-zero exit status).

Only find first few matched files using find

You could pipe the output of find through head:

find . -name '*.txt' | head -n 3

Best Answer

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Find Command – How to Stop After First Match

Only find first few matched files using find

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