# How to check Linux process information? - Linux
Data Science for Political and Social Phenomena
Author: Guillaume Redoulès

# How to check Linux process information?

### How to check Linux process information (CPU usage, memory, user information, etc.)?

You need to use the `ps` command combined with the `grep` command. In the example, we want to check the information on the nginx process :

    ps aux | grep  nginx

It would return the output :

    root      9976  0.0  0.0  12272   108 ?        S<s  Aug12   0:00 nginx: master process /usr/bin/nginx -g pid /run/nginx.pid; daemon on; master_process on;
    http     16780  0.0  0.0  12384   684 ?        S<   Aug12   4:11 nginx: worker process
    http     16781  0.0  0.0  12556   708 ?        S<   Aug12   0:24 nginx: worker process
    http     16782  0.0  0.1  12292   744 ?        S<   Aug12   2:43 nginx: worker process
    http     16783  0.0  0.1  12276   872 ?        S<   Aug12   0:24 nginx: worker process
    admin    17612  0.0  0.1   5120   864 pts/4    S+   11:22   0:00 grep --color=auto nginx

The columns have the following order : USER;PID;%CPU;%MEM;VSZ;RSS;TTY;STAT;START;TIME;COMMAND

- USER = user owning the process
- PID = process ID of the process
- %CPU = It is the CPU time used divided by the time the process has been running.
- %MEM = ratio of the process’s resident set size to the physical memory on the machine
- VSZ = virtual memory usage of entire process (in KiB)
- RSS = resident set size, the non-swapped physical memory that a task has used (in KiB)
- TTY = controlling tty (terminal)
- STAT = multi-character process state
- START = starting time or date of the process
- TIME = cumulative CPU time
- COMMAND = command with all its arguments

### Interactive display

If you want an interactive display showing in real time the statistics of the running process you can use the `top` command. If `htop` is available on you system, use this instead.

### Find an error or bug? Have a suggestion?

Everything on this site is avaliable on GitHub. Head on over and submit an issue. You can also message me directly by email.