In the world of Unix and Linux, ps is a powerful command-line tool used for viewing information about running processes. Two popular variations of this command are ps -ef and ps aux. While they may seem similar, there are key differences in their output and usage. This article aims to shed light on these differences and help you understand when to use which command.
The main difference between ps -ef and ps aux commands is in the format of their output. ps -ef provides a more concise output, while ps aux provides more detailed information about the processes. Additionally, ps -ef displays the UID, while ps aux displays the username. The choice between them depends on the level of detail required for monitoring processes in Unix and Linux systems.
Understanding the ps Command
Before diving into the differences, let’s first understand the ps command. ps stands for “process status”. It is used to provide information about the currently running processes, including their process identification numbers (PIDs).
The ps -ef Command
The ps -ef command is used to display all the currently running processes in the system. Here’s a breakdown of the -ef option:
-e: This option is for selecting all processes.-f: This stands for “full format listing”.
So, ps -ef will display all processes in a full format listing. The output columns are: UID, PID, PPID, C, STIME, TTY, TIME, and CMD.
Here’s what each column represents:
UID: User ID that this process belongs to.PID: Process ID.PPID: Parent process ID (the process that launched this process).C: Processor utilization.STIME: Time the command started.TTY: Terminal type associated with the process.TIME: Cumulative CPU time.CMD: The command that started this process.
The ps aux Command
On the other hand, ps aux also displays all processes of all users, but in a user-oriented format. Here’s what aux stands for:
a: Show processes for all users.u: Display the process’s user/owner.x: Also show processes not attached to a terminal.
The output columns for ps aux are: USER, PID, %CPU, %MEM, VSZ, RSS, TTY, STAT, START, TIME, and COMMAND.
Here’s what each column represents:
USER: The owner of the process.PID: Process ID.%CPU: The percentage of the CPU that this job got.%MEM: The percentage of RAM used by this job.VSZ: Virtual memory usage of entire process.RSS: Resident set size, the non-swapped physical memory that a task has used.TTY: Terminal type associated with the process.STAT: Process status.START: Starting time or date of the process.TIME: Cumulative CPU time.COMMAND: The command that started this process.
Key Differences
The main difference between ps -ef and ps aux lies in the format of the output. ps -ef provides a more concise output, while ps aux provides more detailed information about the processes.
Another key difference is the way they display user information. ps -ef displays the UID, while ps aux displays the username.
Conclusion
Both ps -ef and ps aux are powerful commands for monitoring processes in Unix and Linux systems. The choice between them depends on the level of detail you require. If you need more detailed information, ps aux is the way to go. If you need a more concise output, ps -ef would be the better choice. Understanding these commands and their differences is crucial for effective system administration and troubleshooting.
The main difference lies in the format of the output. ps -ef provides a more concise output, while ps aux provides more detailed information about the processes.
The -e option is used to select all processes.
The -f option stands for "full format listing" in ps -ef, which displays all processes in a detailed format.
The a option in ps aux is used to show processes for all users.
The u option in ps aux is used to display the process’s user/owner.
The x option in ps aux is used to show processes not attached to a terminal.
The UID column in ps -ef represents the User ID that the process belongs to.
The USER column in ps aux represents the owner of the process.
If you need more detailed information about the processes, you should use the ps aux command.
If you need a more concise output, you should use the ps -ef command.
