System Information using the console

There are some really useful commands that can give information about the system directly from the console. Some of them are:

See a list of all the running processes using standard syntax:

# ps ax | less

See a list of all the running processes using BSD syntax:

# ps aux | less

See real-time information about running processes:

# top

Pressing the L, T, M keys while top is running you can toggle the display of Average Load, CPU and Memory usage respectively. The Space key refreshes the display and Q key quits the program. There are a lot more, so you should check the man page.

Memory and SWAP space usage:

# free -m

Use the -m parameter to show the amount of memory in MB instead of bytes.

Check if a program is running:

# ps ax | grep PROGRAM | grep -v grep

Show filesystem and disk space usage:

# df -h

Show disk usage under the current directory

# du -hs

The -h parameter shows sizes in human readable formats (eg MB, GB) and the -s gives only a total. If it’s not used, then information about each subdirectory is shown.

There are a lot more. I’ll add more commands to this post in a future update. Stay tuned!

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