Taking care about disk usage is a very good habit. There are several options for this and now I will only describe df and du commands.
The df utility displays the disk space usage on all mounted filesystems.
[root@abc ~]# df Filesystem 1K-blocks Used Available Use% Mounted on /dev/mapper/VolGroup00-LogVol00 35772016 20297132 13628408 60% / /dev/sda1 101086 17692 78175 19% /boot tmpfs 513044 0 513044 0% /dev/shm
Adding the -T option (type) will print the filesystem type. Also, the good idea is to add -h option because df measures the size in 1K blocks, which is difficult for a desktop user to recalculate.
Now we have
[root@abc ~]# df -h -T Filesystem Type Size Used Avail Use% Mounted on /dev/mapper/VolGroup00-LogVol00 ext3 35G 20G 13G 60% / /dev/sda1 ext3 99M 18M 77M 19% /boot tmpfs tmpfs 502M 0 502M 0% /dev/shm
As you can see, it is much easier to understand.
You can use the du command to determine which files or directories need to be deleted or reduced. A simple du will print usage for the present working directory and its subdirectories, along with the size of each directory.
du directory will print the size of an particular dir.
-h – print the size of the podcasts directory in a more readable format
-c – prints the grand total size of the directory at the end.
-a – displays the file names along with directories
-s – display a summary, without showing all of the subdirectories.
For example, du -ch | grep total prints just one line with the total size of the directory.