If you're running a Linux server, it's important to monitor disk space usage to avoid running out of space.
The df command stands for "disk file system." As the name suggests, it is a command to display the amount of disk space used and available on your filesystems. The df command will provide not only information about overall disk usage but also specific details about individual partitions or mount points.
How to use the df command
To use it, type "df" at the terminal.
The syntax is as follows:
df [OPTION][FILE]
The output of the df command is a table that shows each filesystem and its corresponding size, used space, available space, and percentage of used space.
Example:
df
Output:
Filesystem 1K-blocks Used Available Use% Mounted on
rootfs 146527452 131487592 15039860 90% /
none 146527452 131487592 15039860 90% /dev
none 146527452 131487592 15039860 90% /run
none 146527452 131487592 15039860 90% /run/lock
none 146527452 131487592 15039860 90% /run/shm
none 146527452 131487592 15039860 90% /run/user
tmpfs 146527452 131487592 15039860 90% /sys/fs/cgroup
C:\ 146527452 131487592 15039860 90% /mnt/c
D:\ 164815868 139717888 25097980 85% /mnt/d
G:\ 15728640 4528024 11200616 29% /mnt/g
Suppose you want to see information about a specific filesystem. In that case, you can specify it as an argument to the df command. For example, to see information about the "/C" filesystem only, you would type:
df /mnt/c
Output:
Filesystem 1K-blocks Used Available Use% Mounted on
C:\ 146527452 131492236 15035216 90% /mnt/c
Customizing the df command
You can customize the output of the df command using various options. For example, if you want to see the output in human-readable format (i.e., in kilobytes, megabytes, or gigabytes), you can use the "-h" option.
df -h
Output:
Filesystem Size Used Avail Use% Mounted on
rootfs 140G 126G 15G 90% /
none 140G 126G 15G 90% /dev
none 140G 126G 15G 90% /run
none 140G 126G 15G 90% /run/lock
none 140G 126G 15G 90% /run/shm
none 140G 126G 15G 90% /run/user
tmpfs 140G 126G 15G 90% /sys/fs/cgroup
C:\ 140G 126G 15G 90% /mnt/c
D:\ 158G 134G 24G 85% /mnt/d
G:\ 15G 4.4G 11G 29% /mnt/g
Demonstration with specific filesystem
df -h /mnt/c
Output:
Filesystem Size Used Avail Use% Mounted on
C:\ 140G 126G 15G 90% /mnt/c
Disk space is often tight on servers. If you're running low on disk space, use the df command to quickly find out which filesystems are taking up the most space. To do this, pass the -t option to df followed by a type of filesystem. For example, this will show you only ext filesystems:
df -t ext
More Options
You can also specify the information you want to see in the output. For example, to see the size and percentage used only, use df command like this:
df -h --output='size','pcent' /mnt/c
Output:
Size Use%
140G 90%
If you need a list of all available options for the df command, you can use the --help option:
df --help
Conclusion
That's it for this introduction to the df command. As you can see, it's a helpful tool for understanding your disk usage and finding ways to free up space on your system. So try it and see what information it can provide about your system's disk space usage!
Thanks for reading.
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