How to clean up unnecessary files

Question

Please suggest me any particular unnecessary file that I can clean to back everything to normal condition(temporarily). (i.e. any log or archieve or anything ). My var/log has only 40MB and Home directory has 3GB of space(so I believe that's not a problem). Other than that what I can clean up to make space.

[user@host]$ df -h
Filesystem            Size  Used Avail Use% Mounted on
/dev/mapper/vg_inamivm-lv_root
                       18G   17G     0 100% /
tmpfs                 1.9G     0  1.9G   0% /dev/shm
/dev/sda1             485M   71M  389M  16% /boot

I am in a debian machine.

UPDATE1:

output of cd /; du -sxh *

6.1M    bin
61M     boot
156K    dev
22M        etc
3.3G    home
306M    lib
18M     lib64
16K     lost+found
4.0K    media
4.0K    mnt
408K    opt
du: cannot access `proc/18605/task/18605/fd/4': No such file or directory
du: cannot access `proc/18605/task/18605/fdinfo/4': No such file or directory
du: cannot access `proc/18605/fd/4': No such file or directory
du: cannot access `proc/18605/fdinfo/4': No such file or directory
0       proc
208K    root
9.7M    sbin
0       selinux
4.0K    srv
0       sys
8.0K    tmp
536M    usr
187M    var

Update2

Output of ls -la /

dr-xr-xr-x.  22 root root  4096 Aug  7 08:42 .
dr-xr-xr-x.  22 root root  4096 Aug  7 08:42 ..
-rw-r--r--.   1 root root     0 Aug  7 08:42 .autofsck
dr-xr-xr-x.   2 root root  4096 Mar 28 16:53 bin
dr-xr-xr-x.   5 root root  1024 Mar 28 16:54 boot
drwxr-xr-x.  16 root root  3580 Sep  9 03:13 dev
drwxr-xr-x.  69 root root  4096 Aug 23 09:19 etc
drwxr-xr-x.   9 root root  4096 Jun 29 16:10 home
dr-xr-xr-x.   8 root root  4096 Mar  7  2012 lib
dr-xr-xr-x.   9 root root 12288 Mar 28 16:53 lib64
drwx------.   2 root root 16384 Mar  7  2012 lost+found
drwxr-xr-x.   2 root root  4096 Sep 23  2011 media
drwxr-xr-x.   2 root root  4096 Sep 23  2011 mnt
drwxr-xr-x.   3 root root  4096 Mar  7  2012 opt
dr-xr-xr-x. 355 root root     0 Aug  7 08:42 proc
dr-xr-x---.   5 root root  4096 Aug 17 18:27 root
dr-xr-xr-x.   2 root root  4096 May  2 09:13 sbin
drwxr-xr-x.   7 root root     0 Aug  7 08:42 selinux
drwxr-xr-x.   2 root root  4096 Sep 23  2011 srv
drwxr-xr-x.  13 root root     0 Aug  7 08:42 sys
drwxrwxrwt.   3 root root  4096 Sep 13 03:37 tmp
drwxr-xr-x.  13 root root  4096 Mar 28 17:53 usr
drwxr-xr-x.  18 root root  4096 Mar  7  2012 var

There is no universal answer here. Run following commands as root, wait for a while and paste your results: cd /; du -sxh *. It will sum up the size of all main directories on your server. Then, we will have a clue. You can also enter this big directory with cd and run du command inside of it to get deeper. — Krzysztof Adamski, Sep 13 '12 at 13:33
@KrzysztofAdamski Thanks for a quick reply. I have updated the question with output of cd /; du -sxh * — Subhransu Mishra, Sep 13 '12 at 13:43
@Subhransu Based on what you are seeing it appears as if you have a file that has been removed while still open. — Karlson, Sep 13 '12 at 13:50
@Karlson I really don't understand if you have a file that has been removed while still open . Please explain. Please let me know what other output could be viable so that you can help me. — Subhransu Mishra, Sep 13 '12 at 13:54
Did you remove any big files recently? Like log files or something like this? — Krzysztof Adamski, Sep 13 '12 at 14:04
@KrzysztofAdamski No, I have not deleted any log file(as I do not know what file to delete). — Subhransu Mishra, Sep 13 '12 at 14:10
Well, the easiest way to find out would be to reboot the server. It would kill all the processes so all the files would be closed which would delete them. You can try to restart syslogd, just in case with /etc/init.d/rsyslog restart and since you have a lot of apache processes, i would also try to restart apache itself with /etc/init.d/apache2 restart. Check if it make some free space on your filesystem. — Krzysztof Adamski, Sep 13 '12 at 14:15
@Subhransu The situation is simple. Process foo has opened a file called bar then user Subharansu came in and did rm -f bar. File is still opened by the running process foo and space it claims is unavailable for use until foo exits. — Karlson, Sep 13 '12 at 14:19
You can also check the output of lsof | awk ' { print $8,$9 }' | sort -n | uniq | tail -n 30 — Krzysztof Adamski, Sep 13 '12 at 14:20
@KrzysztofAdamski The system not able understand the command bash: lsof: command not found and I have tried it including the path /usr/sbin/lsof but still not able to recognize the command. Is it safe to do reboot if system do not have any storage space? — Subhransu Mishra, Sep 13 '12 at 14:28
It is possible that you don't have this command installed, then. It should be safe to reboot without storage space. But as I don't know what exactly happened on your system, I can't guarantee that it will boot up correctly (but it should). — Krzysztof Adamski, Sep 13 '12 at 14:30
Maybe you have files in the /-directory? You might want to check with ls -la / — harp, Sep 13 '12 at 14:09

score 55 · Answer 1 · edited Dec 05 '19 at 05:02

daisy's answer to use a graphical tool to visually find large files and directories is probably the best method. However, do note that "graphical tool" does not mean "requires an X server"! The wonderful ncdu program provides the graphical output in the CLI, and works perfectly on remote servers via SSH:

$ ncdu /

.  43.7GiB [##########] /home
.   5.9GiB [#         ] /usr
    1.1GiB [          ] /lib
.   1.1GiB [          ] /var
  736.9MiB [          ] /opt
. 324.6MiB [          ] /tmp
  218.4MiB [          ] /boot
.  63.8MiB [          ] /etc
   10.0MiB [          ] /sbin
    8.8MiB [          ] /bin
    3.3MiB [          ] /lib32
.   1.0MiB [          ] /run
   64.0KiB [          ] /build
!  16.0KiB [          ] /lost+found
    8.0KiB [          ] /media
    8.0KiB [          ] /mnt
    8.0KiB [          ] /.config
    4.0KiB [          ] /dev
    4.0KiB [          ] /lib64
e   4.0KiB [          ] /srv
e   4.0KiB [          ] /selinux
!   4.0KiB [          ] /root
e   4.0KiB [          ] /cdrom
.   0.0  B [          ] /proc
.   0.0  B [          ] /sys
@   0.0  B [          ]  initrd.img.old
@   0.0  B [          ]  initrd.img
@   0.0  B [          ]  vmlinuz.old

Then, after entering /var/ for instance:

. 395.3MiB [##########] /tmp
. 365.0MiB [######### ] /cache
. 297.8MiB [#######   ] /lib
   16.1MiB [          ] /backups
.   8.0MiB [          ] /log
.  56.0KiB [          ] /spool
   40.0KiB [          ] /games
    8.0KiB [          ] /www
e   4.0KiB [          ] /opt
e   4.0KiB [          ] /mail
e   4.0KiB [          ] /local
e   4.0KiB [          ] /crash
@   0.0  B [          ]  lock
@   0.0  B [          ]  run

Install easily on Debian or Ubuntu:

$ sudo apt-get install ncdu

Install easily on CentOS as root:

# yum install ncdu

Oh wow, didn't know ncdu existed. All this time, I use du -sh ./* 2> /dev/null | sort -rh. — annahri, Dec 31 '21 at 19:51

score 17 · Accepted Answer · answered Sep 13 '12 at 15:07

17

The best way of finding out disk consuming, is using graphical software like baobab:

Launch it with sudo baobab /

enter image description here

answered Sep 13 '12 at 15:07

daisy

54,555

Will it work in remote server ? – Subhransu Mishra Sep 13 '12 at 18:26
@Subhransu Sure, if you connect with X forwarding (ssh -X or ForwardX11 yes in ~/.ssh/config). However, if it isn't installed you might not have enough space to install it and the requisite directory. – Gilles 'SO- stop being evil' Sep 13 '12 at 23:34
3

See my answer below for a graphical tool that does not require an X server and requires very little server space. – dotancohen Jan 20 '14 at 12:29

score 7 · Answer 3 · answered Sep 13 '12 at 14:34

7

Debian offers a utility called cruft IIRC that lists files that could possibly be uneeded on your system.

answered Sep 13 '12 at 14:34

LawrenceC

10,992

1

How can that be used? – nilon Nov 08 '19 at 04:07

score 6 · Answer 4 · edited Oct 22 '14 at 22:28

6

make a new file in /bin called treesize

chmod +x /bin/treesize

paste this in it.

#/bin/sh
du -k --max-depth=1 | sort -nr | awk '
     BEGIN {
        split("KB,MB,GB,TB", Units, ",");
     }
     {
        u = 1;
        while ($1 >= 1024) {
           $1 = $1 / 1024;
           u += 1
        }
        $1 = sprintf("%.1f %s", $1, Units[u]);
        print $0;
     }
    '

Output looks like this.

#treesize
3.0 GB .
1.1 GB ./usr
759.9 MB ./var
353.3 MB ./root
307.1 MB ./opt
270.7 MB ./lib
98.6 MB ./home
60.1 MB ./boot
9.8 MB ./etc
8.3 MB ./bin
8.1 MB ./sbin
268.0 KB ./run
40.0 KB ./tmp
16.0 KB ./lost+found

edited Oct 22 '14 at 22:28

HalosGhost

4,790

answered Oct 22 '14 at 22:08

Duke

61
1
1

1

or this du -hsx /* | sort -rh | head -n 40 – Alejandro Feb 12 '20 at 01:50
@Alejandro: it's not really the same - at all. – Seamus Mar 29 '24 at 06:59
I like this - very neat! – Seamus Mar 29 '24 at 06:59

score 5 · Answer 5 · edited Apr 13 '17 at 12:22

I've found some very useful commands on this post at Askubuntu.com. Paraphrasing:

Show top 10 biggest subdirs in the current dir: du -sk * | sort -nr | head -10
Use filelight/kDirStat/baobab to see where the disk space is going visually
Check if you have old kernels for deletion: ls -lh /boot
Clean packages: sudo apt-get autoremove and sudo apt-get autoclean
See list of all installed packages, sorted by size: dpkg-query -W --showformat='${Installed-Size} ${Package}\n' | sort -nr | less
Clean unused language files with translations: sudo apt-get install localepurge
Check content of /var/tmp/: du -sh /var/tmp/
Check also man deborphan
Search for big files: find / -type f -size +1024k or find / -size +50000 -exec ls -lahg {} \;

score 5 · Answer 6 · answered Feb 03 '13 at 18:06

5

You can check for deleted files with lsof | grep -i deleted Then you can see if a process is hanging on to an inode that you think was deleted. If so, restart the parent process to release the old (deleted) file.

answered Feb 03 '13 at 18:06

joshcody

51

score 3 · Answer 7 · answered Sep 14 '12 at 08:06

This will give you the biggest files on your FS and maybe you will find there some files which can be deleted.

find / -xdev -type f -size +100000c -exec ls -la {} \; 2>/dev/null | sort -nk5 | tail -20

If you need longer output, just change number after tail command.
Please post output from:

df -h /
du -shx /

Both commands should show similar used space of your FS.

score 0 · Answer 8 · answered May 19 '21 at 05:29

find . -atime +180 | xargs ls -al | sort -u -n -k5 | numfmt --to=iec --field=5

find all files in . whos access time is over 180 days old
show file size
sort by 5th column, numerical
format 5th column to human readable

Useful links about access time:

How to clean up unnecessary files

8 Answers8

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