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http://www.saltycrane.com/blog/2007/12/how-to-use-grep-and-find-to-search/
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I often use grep to search through the text of my
files for search terms such as a variable or function name. For
example, since xrange
is being
removed from Python 3000, I'd like to search for all the
occurrences of xrange. Here is how to search all my Python
files in the current directory:
$ grep --color "xrange" *.py
Which outputs something like:
dol2lol.py: for i in xrange(len(dol[keylist[0]])):
dol2lol.py: for i in xrange(len(dol[keylist[0]]))]
lol2lod.py:# for i in xrange(len(locols[0])):
lol2lod.py:# for j in xrange(len(keylist)):
lol2lod.py: return [dict([(keylist[j], locols[j][i]) for j in xrange(len(keylist))])
lol2lod.py: for i in xrange(len(locols[0]))]
table_modelview.py: for row in xrange(nrows):
The above command only works for the current directory. If I want
to recurse into subdirectories, I can use:
$ grep -r --color "xrange" .
However, this command often produces too many results because I
cannot specify which files to search. To gain better control over
which files are searched, I can use grep in combination
with the find command. Here is an example which recurses into
subdirectories and searches all my Python files
for xrange. (I know it's hard to imagine
when xrange would be inside anything other than a Python
file, but hey, it's just an example.
$ find . -name '*.py' -exec grep --color 'xrange' {} +
Usually,
using find with -exec is very
slow and xargs is used to gain performance. However,
thanks to the tip from Some
notes about find, I used the + expression at the end of
the commandline which avoids the fork/exec overhead,
without using xargs.
As a final example, here is how I search for the
text #define in all files in my current directory,
excluding my backup files (*~, *.orig, *.bak). In this example, I
don't want to recurse into directories, so I
set -maxdepth
to 1. Note, Some
notes about find has some other options about limiting the depth
portably, but this option worked for me. Note, this is similar to the
command I use as my Emacs grep.
find . -maxdepth 1 ! -regex '.*~$' ! -regex '.*\.orig$' \
! -regex '.*\.bak$' -exec grep --color "#define" {} +
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