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to process, it first carries out the selection restrictions implied by the command-line options, and if those tests succeed, it hands the name off to an internal action routine. The default action is just to print the name on standard output, but the -exec option can provide a command template into which the name is substituted, and the command is then executed. Antiquated implementations of find required an explicit -print option to produce output, but fortunately, that design blunder has been fixed in every current implementation that we've tested, and in POSIX.

Automated execution of commands on selected files is both powerful and extremely dangerous. If that command is destructive, it may be better to let find produce the list in a temporary file first, and then have a competent human carefully examine that list before deciding whether to hand it off to some command for further automated processing.

Shell scripts that use find for destructive purposes must be written carefully, and then debugged with dry runs that, for example, insert the echo command at the start of the destructive command so that you can see what would have been done without actually doing it.

We are now ready for the simplest example: a bare find finds everything in the current directory tree. As before, we start with an empty directory, then populate it with a few empty files:

$ ls

Verify that we have an empty directory

$ mkdir -p sub/sub1

Create a directory tree

$ touch one two .uno .dos

Create some empty top-level files

$ touch sub/three sub/sub1/four

Create some empty files deeper in the tree

$ find

Find everything from here down

.

./sub

./sub/sub1

./sub/sub1/four

./sub/three

./one

./two

./.uno

./.dos

That jumbled list is easily sorted:

$ find | LC_ALL=C sort

Sort find's output into traditional order

.

./.dos

./.uno

./one

./sub

./sub/sub1

./sub/sub1/four

./sub/three

./two

We set LC_ALL to get the traditional (ASCII) sort order, since modern sort implementations are locale-aware, as we described in Section 4.1.1.

find has a useful option, -ls, that gives output vaguely similar to what ls -liRs would give. However, it lacks further options to control the format of this verbose display:

$ find -ls

Find files, and use ls-style output

1451550 4 drwxr-xr-- 3 jones devel 4096 Sep 26 09:40 .

1663219 4 drwxrwxr-x 3 jones devel 4096 Sep 26 09:40 ./sub

1663220 4 drwxrwxr-x 2 jones devel 4096 Sep 26 09:40 ./sub/sub1

1663222 0 -rw-rw-r-- 1 jones devel 0 Sep 26 09:40 ./sub/sub1/four

1663221 0 -rw-rw-r-- 1 jones devel 0 Sep 26 09:40 ./sub/three

1451546 0 -rw-rw-r-- 1 jones devel 0 Sep 26 09:40 ./one

1451547 0 -rw-rw-r-- 1 jones devel 0 Sep 26 09:40 ./two

1451548 0 -rw-rw-r-- 1 jones devel 0 Sep 26 09:40 ./.uno

1451549 0 -rw-rw-r-- 1 jones devel 0 Sep 26 09:40 ./.dos

$ find -ls | sort -k11

Find files, and sort by filename

1451550 4 drwxr-xr-- 3 jones devel 4096 Sep 26 09:40 .

1451549 0 -rw-rw-r-- 1 jones devel 0 Sep 26 09:40 ./.dos

1451548 0 -rw-rw-r-- 1 jones devel 0 Sep 26 09:40 ./.uno

1451546 0 -rw-rw-r-- 1 jones devel 0 Sep 26 09:40 ./one

1663219 4 drwxrwxr-x 3 jones devel 4096 Sep 26 09:40 ./sub

1663220 4 drwxrwxr-x 2 jones devel 4096 Sep 26 09:40 ./sub/sub1

1663222 0 -rw-rw-r-- 1 jones devel 0 Sep 26 09:40 ./sub/sub1/four

1663221 0 -rw-rw-r-- 1 jones devel 0 Sep 26 09:40 ./sub/three

1451547 0 -rw-rw-r-- 1 jones devel 0 Sep 26 09:40 ./two

For comparison, here is how ls displays the same file metadata:

$ ls -liRs *

Show ls recursive verbose output

752964 0 -rw-rw-r-- 1 jones devel 0 2003-09-26 09:40 one

752965 0 -rw-rw-r-- 1 jones devel 0 2003-09-26 09:40 two

sub:

total 4

752963 4 drwxrwxr-x 2 jones devel 4096 2003-09-26 09:40 sub1

752968 0 -rw-rw-r-- 1 jones devel 0 2003-09-26 09:40 three

sub/sub1:

total 0

752969 0 -rw-rw-r-- 1 jones devel 0 2003-09-26 09:40 four

Now let's give the find command some file patterns:

$ find 'o*'

Find files in this directory starting with "o"

one

$ find sub

Find files in directory sub

sub

sub/sub1

sub/sub1/four

sub/three