Ps

In most Unix-like operating systems, the ps program displays the currently-running processes. A related Unix utility named top provides a real-time view of the running processes.

The ps command is analogous to the Microsoft Windows tasklist command. In Windows PowerShell, ps is a predefined command alias for the Get-Process cmdlet which basically serves the same purpose.

Examples

For example:

# ps
  PID TTY          TIME CMD
 7431 pts/0    00:00:00 su
 7434 pts/0    00:00:00 bash
18585 pts/0    00:00:00 ps

Users can also utilize the ps command in conjunction with the grep command to find information about one process, such as its process id.

An example of this is:

# ps -A | grep firefox-bin
11778 ?        02:40:08 firefox-bin
11779 ?        00:00:00 firefox-bin

Options

ps has many options. On operating systems that support the UNIX and POSIX standards, ps commonly runs with the options -ef, where "-e" selects every process and "-f" chooses the "full" output format. Another common option on these systems is -l, which specifies the "long" output format.

Most systems derived from BSD fail to accept the POSIX and UNIX standard options because of historical conflicts (for example, the "e" or "-e" option will cause the display of environment variables). On such systems, ps commonly runs with the non-standard options aux, where "a" lists all processes on a terminal, including those of other users, "x" lists all processes without controlling terminals and "u" adds a column for the controlling user for each process. Note that, for maximum compatibility when using this syntax, there is no "-" in front of the "aux". Also you can add 'www' after aux, like "ps auxwww" for complete information about the process including all parameters.

See also

• top
• pstree
• pgrep
• kill
• List of Unix programs

External links

• ps — Specification from the Single Unix Specification
• Show all running processes in Linux using ps command
• ps(1): report a snapshot of the current processes – Linux man page