ps: View detailed information of all processes

Overview

ps -ef lists all processes running on the system with detailed information including User ID, Process ID, Parent Process ID, CPU usage, start time, terminal, CPU time, and the command being executed. This is useful for understanding the current system state and identifying specific processes.

ps -ef Output Column Descriptions

The main output columns of the ps -ef command are as follows:

UID: User ID of the process owner
PID: Process ID
PPID: Parent Process ID
C: CPU utilization (CPU usage over a recent period)
STIME: Process start time
TTY: Terminal associated with the process (tty, pts, etc.)
TIME: Total CPU time consumed by the process
CMD: Command and its arguments

Key Options

The ps command allows controlling the output format through various options. The 'ps -ef' combination is a union of the '-e' and '-f' options.

Process Selection and Output Format

Generated command:

Try combining the commands.

Description:

`ps` Executes the command.

Combine the above options to virtually execute commands with AI.

Usage Examples

Various usage examples of the ps -ef command.

Display detailed information for all processes

ps -ef

Outputs detailed information for all processes running on the system.

Search for specific processes

ps -ef | grep sshd

Combines with the grep command to search for processes containing a specific keyword (e.g., sshd process).

Search for processes of a specific user

ps -ef | grep root

Searches only for processes executed by a specific user (e.g., 'root').

View top N processes with headers

ps -ef | head -n 5

When the output is extensive, displays the top few lines including headers. (e.g., top 5 lines)

Check information for a specific PID

ps -ef | grep 1234

Checks detailed information for a process with a specific PID (e.g., 1234).

Tips & Notes

ps -ef is a powerful tool for understanding system status, but its output can be extensive, so it's common to use it in conjunction with other commands like grep.

ps aux vs ps -ef

The ps command supports two main option styles: System V style (e.g., -ef) and BSD style (e.g., aux). Both display all processes, but the output format and some information may differ. -ef is the 'full' format in System V style, while aux is the 'all users' and 'full' format in BSD style.

ps -ef: System V style, all processes, detailed information (UID, PID, PPID, C, STIME, TTY, TIME, CMD)
ps aux: BSD style, all user processes, detailed information (USER, PID, %CPU, %MEM, VSZ, RSS, TTY, STAT, START, TIME, COMMAND)

Filtering with grep

The output of ps -ef can be very long, so it's always recommended to use it with grep to quickly find the information you need. For example, 'ps -ef | grep httpd' will only show httpd-related processes.

Terminating Processes

You can use the PID identified with ps -ef to terminate a specific process using the kill command. For example: 'kill ' or 'kill -9 ' (force kill).