How can you view running processes on a Linux system using the 'ps' command?

1 What is the 'ps' command?

The 'ps' command is a Linux command that displays information about the processes that are currently running on your system. The name 'ps' stands for process status. The 'ps' command can show you various details about the processes, such as their process ID (PID), command name, CPU and memory usage, start time, parent process ID (PPID), and more. You can use the 'ps' command to identify the processes that consume the most resources, troubleshoot problems, or kill unwanted processes.

2 How to use the 'ps' command?

To use the 'ps' command, you need to open a terminal window and type 'ps' followed by some options and arguments. The options and arguments determine what kind of information and format the 'ps' command will display. There are two types of options: UNIX options and BSD options. UNIX options start with a dash (-) and BSD options do not. You can mix both types of options, but you need to separate them with a space. For example, 'ps -ef' and 'ps aux' are both valid commands, but 'ps -aux' is not.

3 What are some common options for the 'ps' command?

The 'ps' command has several common options, such as -e or -A which displays all processes on the system, including those from other users. The -f option shows the full format of the output, including more details about the processes like PPID, terminal, and user. The -u option shows a user-oriented format of the output with user name, CPU and memory percentage, and process status. Additionally, the a option shows all processes except session leaders and those not associated with a terminal. Similarly, the u option also shows the user-oriented format with BSD style while the x option displays all processes, including those not associated with a terminal.

5 How to sort the output of the 'ps' command?

Another useful feature of the 'ps' command is that you can sort the output by a specific field or column, such as the PID, the CPU, the memory, or the start time. You can use the --sort option to sort the output of the 'ps' command, followed by a field name and a sign. The sign can be either + or -, indicating ascending or descending order. For example, 'ps --sort -cpu' sorts the output by the CPU percentage in descending order, showing the most CPU-intensive processes first.

6 How to customize the output of the 'ps' command?

Finally, you can also customize the output of the 'ps' command by selecting which fields or columns you want to display and how you want to format them. You can use the -o or --format option to customize the output of the 'ps' command, followed by a list of field names and optional modifiers. The field names can be either standard or custom, and the modifiers can be used to change the width, alignment, or header of the fields. For example, 'ps -o pid,comm,args' shows the process ID, the command name, and the arguments of each process. You can also use the --headers option to show or hide the headers of the output.