Linux / UNIX: Finding and locating files with find command part # 2

Posted on in Categories CentOS, File system, FreeBSD, GNU/Open source, Howto, Linux, Linux desktop, OpenBSD, RedHat/Fedora Linux last updated July 23, 2005

In the first part we talked about find command basic usage.

Now let us see how to use find command
(a) To gain lots of useful information about users and their files

(b) Monitor and enhance the security of system using find command

Finding all set user id files

setuid (“suid”) and setgid are access right flags that can be assigned to files and directories on a Unix based operating system. They are mostly used to allow users on a computer system to execute binary executables with temporarily elevated privileges in order to perform a specific task.
# find / -perm +u=s
OR
# find / -perm +4000

See also, shell script to find all programs and scripts with setuid set on.

Finding all set group id files

# find / -perm +g=s
OR
# find / -perm +2000

See also, shell script to find all programs and scripts with setgid bit set on.

Finding all large directories

To find all directories taking 50k (kilobytes) blocks of space. This is useful to find out which directories on system taking lot of space.
# find / -type d -size +50k
Output:

/var/lib/dpkg/info
/var/log/ksymoops
/usr/share/doc/HOWTO/en-html
/usr/share/man/man3

Finding all large files on a Linux / UNIX

# find / -type f -size +20000k
Output:

var/log/kern.log
/sys/devices/pci0000:00/0000:00:02.0/resource0
/sys/devices/pci0000:00/0000:00:00.0/resource0
/opt/03Jun05/firefox-1.0.4-source.tar.bz2

However my favorite hack to above command is as follows:
# find / -type f -size +20000k -exec ls -lh {} \; | awk '{ print $8 ": " $5 }'

/var/log/kern.log: 22M
/sys/devices/pci0000:00/0000:00:02.0/resource0: 128M
/sys/devices/pci0000:00/0000:00:00.0/resource0: 256M
/opt/03Jun05/firefox-1.0.4-source.tar.bz2: 32M

Above command will find all files block size greater than 20000k and print filename followed by the file size. Output is more informative as compare to normal find command output 😀

Posted by: Vivek Gite

The author is the creator of nixCraft and a seasoned sysadmin and a trainer for the Linux operating system/Unix shell scripting. He has worked with global clients and in various industries, including IT, education, defense and space research, and the nonprofit sector. Follow him on Twitter, Facebook, Google+.

12 comment

  1. Thanks a bunch, that command string was just what I was looking for, and I had looked at around 20 other sites with nothing near as good. (As Sharjeel said $9 is the filename, at least on my system.)

    To tweak the output and have the file sizes in a column, add this to the end:

    | column -t

    this just expands the tabs to even the columns out.

  2. The find command for setuid files isnt that useful. Almost never is the setuid bit the only bit set. The better way is
    # find / -perm -u=s
    or
    # find / -perm -4000

    Those will find any files with the setuid bit set. Not just files with only the setuid bit set.

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