Linux and UNIX find command

December 26, 2011 by: Youzhny


In Unix-like and some other operating systems, find is a command-line utility that searches through one or more directory trees of a file system, locates files based on some user-specified criteria and applies a user-specified action on each matched file. The possible search criteria include a pattern to match against the file name or a time range to match against the modification time or access time of the file. By default, find returns a list of all files below the current working directory.

Linux: Finding and Locating files with find command
From current directory
find . -name ‘my*’

Files only
find . -name “my*” -type f

Commands
The previous examples created listings of results because, by default, find executes the ‘-print’ action. (Note that early versions of the find command had no default action at all; therefore the resulting list of files would be discarded, to the bewilderment of users.)
find . -name “my*” -type f -ls

Search all directories
find / -type f -name “myfile” -print

Search all but one directory subtree
find / -path excluded_path -prune -o -type f -name myfile -print

Specify a directory
find /home/weedly -name “myfile” -type f -print

Search several directories
find local /tmp -name mydir -type d -print

Ignore errors
If you’re doing this as a user other than root, you might want to ignore permission denied (and any other) errors. Since errors are printed to stderr, they can be suppressed by redirecting the output to /dev/null. The following example shows how to do this in the bash shell:
find / -name “myfile” -type f -print 2>/dev/null
If you are a csh or tcsh user, you cannot redirect stderr without redirecting stdout as well. You can use sh to run the find command to get around this:
sh -c find / -name “myfile” -type f -print 2>/dev/null
An alternate method when using csh or tcsh is to pipe the output from stdout and stderr into a grep command. This example shows how to suppress lines that contain permission denied errors.
find . -name “myfile” |& grep -v “Permission denied”
Find any one of differently named files
find . \( -name “*jsp” -o -name “*java” \) -type f -ls

Execute an action
find /var/ftp/mp3 -name “*.mp3″ -type f -exec chmod 644 {} \;
This command changes the permissions of all files with a name ending in .mp3 in the directory /var/ftp/mp3. The action is carried out by specifying the option -exec chmod 644 {} \; in the command. For every file whose name ends in .mp3, the command chmod 644 {} is executed replacing {} with the name of the file. The semicolon (backslashed to avoid the shell interpreting it as a command separator) indicates the end of the command. Permission 644, usually shown as rw-r–r–, gives the file owner full permission to read and write the file, while other users have read-only access. In some shells, the {} must be quoted.
Note that the command itself should *not* be quoted; otherwise you get error messages like
find: echo “mv ./3bfn rel071204″: No such file or directory
which means that find is trying to run a file called ‘echo “mv ./3bfn rel071204″‘ and failing.
If running under Windows, don’t include the backslash before the semicolon:
find . -exec grep blah {} ;
If you will be executing over many results, it is more efficient to pipe the results to the xargs command instead. xargs is a more modern implementation, and handles long lists in a more intelligent way. The print0 option can be used with this.
The following command will ensure that filenames with whitespaces are passed to the executed COMMAND without being split up by the shell. It looks complicated at first glance, but is widely used.
find . -print0 | xargs -0 COMMAND
The list of files generated by find (whilst it is being generated) is simultaneously piped to xargs, which then executes COMMAND with the files as arguments. See xargs for more examples and options.
Search for a string
This command will search for a string in all files from the /tmp directory and below:
find /tmp -exec grep “search str – + – = +
The /dev/null argument is used to show the name of the file before the text that is found. Without it, only the text found is printed. An equivalent mechanism is to use the “-H” or “–with-filename” option to grep:
find /tmp -exec grep -H “search string” ‘{}’ \; -print
GNU grep can be used on its own to perform this task:
grep -r “search string” /tmp
Example of search for “LOG” in jsmith’s home directory
find ~jsmith -exec grep “LOG” ‘{}’ /dev/null \; -print
/home/jsmith/scripts/errpt.sh:cp $LOG $FIXEDLOGNAME
/home/jsmith/scripts/errpt.sh:cat $LOG
/home/jsmith/scripts/title:USER=$LOGNAME
Example of search for the string “ERROR” in all xml files in the current directory and all sub-directories
find . -name “*.xml” -exec grep “ERROR” ‘{}’ \; -print
The double quotes (” “) surrounding the search string and single quotes (‘ ‘) surrounding the braces are optional in this example, but needed to allow spaces and other special characters in the string.
[edit]Search for all files owned by a user
find . -user
Search in case insensitive mode
find . -iname “MyFile*”
If the -iname switch is not supported on your system then workaround techniques may be possible such as:
find . -name “[mM][yY][fF][iI][lL][eE]*”
This uses Perl to build the above command for you:
echo “‘MyFile*’” |perl -pe ‘s/([a-zA-Z])/[\L\1\U\1]/g;s/(.*)/find . -name \1/’|sh
[edit]Search files by size
Example of searching files with size between 100 kilobytes and 500 kilobytes.
find . -size +100k -a -size -500k
Search files by name and size
find /usr/src -not \( -name “*,v” -o -name “.*,v” \) ‘{}’ \; -print
This command will search in the /usr/src directory and all sub directories. All files that are of the form ‘*,v’ and ‘.*,v’ are excluded. Important arguments to note are:
-not means the negation of the expression that follows
\( means the start of a complex expression.
\) means the end of a complex expression.
-o means a logical or of a complex expression.
In this case the complex expression is all files like ‘*,v’ or ‘.*,v’
for file in `find /opt \( -name error_log -o -name ‘access_log’ -o -name ‘ssl_engine_log’ -o -name ‘rewrite_log’ -o
-name ‘catalina.out’ \) -size +300000k -a -size -5000000k`; do cat /dev/null > $file; done
The units should be one of [bckw], ‘b’ means 512-byte blocks, ‘c’ means byte, ‘k’ means kilobytes and ‘w’ means 2-byte words. The size does not count indirect blocks, but it does count blocks in sparse files that are not actually allocated.

Search files with file type .xml include keyword ”kee”
find . -name “*.xml” -print | xargs grep “kee”

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