1. Linux 103 Training MOdule
Basic System Mgmt

2. This presentation will cover the following commandsdf
free

3. df command
df command in Linux provides disk space usage information of file systems.
$ df
Filesystem 1K-blocks Used Available Use% Mounted on /dev/sda % /
tmpfs % /dev/shm
/dev/sdb % /home/oracle

4. Option -h stands for “human” readable format.
G is used for gigabytes and M is used for megabytes.
$ df -h
Filesystem Size Used Avail Use% Mounted on
/dev/sda G 6.0G 114G 5% /
tmpfs G G 0% /dev/shm
/dev/sdb G 115M 28G 1% /home/oracle
/dev/sdc G 70M 522G 1% /home/data
Display Grand Total in the Output
Display a grand total of every column then we can use the ‘–total’ flag.
$ df -h --total
total G 6.2G 668G 1%

5. Free command Display amount of free and used memory in the system
By default without any options, free command shows the used and free space of physical and swap memory in KB units as shown below,
$ free
total used free shared buffers cached
Mem:
-/+ buffers/cache:
Swap:
2. Switch the free Output in KB, or MB, or GB
Free allows to display the size of memory space in bytes or KB or MB or GB as shown below,
$ free -b
Mem:
-/+ buffers/cache:
Swap:

6. $ free -k
total used free shared buffers cached
Mem:
-/+ buffers/cache:
Swap:
$ free -m
Mem:
-/+ buffers/cache:
Swap:
To display the totals line at the end, execute free command with -t option
$ free -t
Mem:
-/+ buffers/cache:
Total: