Understanding the output of linux ps command<\/h3>\n
Since all the commands of ps are used with options, let us see what happens when we simply run the ps command with no options at all.<\/p>\n
As you can see, in the above output there are 4 columns with different names, let us look at what they stand for before we talk about the option sued with the ps command.<\/p>\n This column tells the Process identity of the running command.<\/p>\n This column tells the type of terminal the command is running on.<\/p>\n This column tells how much time of the CPU was taken by the command<\/p>\n This column tells the name of the command.<\/p>\n In the syntax of the ps command, there is a field for entering options that take in a range of available options which specify how the ps command should work and how the output should be formatted. Let us take a look at some of the available options of the ps command:<\/p>\n This option lists all the currently running processes.<\/p>\n This option lists the currently running processes in full format.<\/p>\n This option lists the process for the user that you specified.<\/p>\n This option lists the process for the command you specified.<\/p>\n This option lists the processes with the (PID) process identity you specified.<\/p>\n This option lists the processes with the PPID you specified.<\/p>\n This option shows the process in the hierarchy.<\/p>\n This option lists all the threads for a particular process.<\/p>\n This option finds the memory leak if there is any.<\/p>\n This option shows the security information.<\/p>\n This option shows the process running by the root.<\/p>\n Now that we have laid down the fundamentals, let us look at 20 beautiful practical commands of ps in the terminal.<\/p>\n If you want to display all the processes for the current shell, run the ps command with no options at all.<\/p>\n If you want to display every single active process on a Linux system in the generic Unix\/Linux format, you can either use the option \u201c-e\u201d or \u201c-a\u201d as shown:<\/p>\n If you want to list all the currently running processes in BDS format, you can either use \u201cau\u201d or \u201caxu\u201d<\/p>\n If you want to print all the currently running processes in full format, combine the option \u201c-f\u201d with the option \u201c-e\u201d as shown:<\/p>\n To select all processes owned by you use the option \u201c-x\u201d as shown:<\/p>\n If you want to display a user\u2019s processes by real user ID, use the option \u201c-U\u201d followed by the name of the user, as shown:<\/p>\n If you want to list every process running with root user privileges (real & effective ID) in user format, use the option \u201c-U root -u root\u201d as shown:<\/p>\n To list all processes owned by a certain group (real group ID (RGID) or name), use the option \u201cG\u201d as shown:<\/p>\n To list processes by process identity use the option \u201c-p\u201d as shown:<\/p>\n To list processes by parent process identity use the option \u201c–ppid\u201d as shown:<\/p>\n If you want to display multiple processes by specifying their process identity, you can use the option \u201c-p\u201d followed by the process identities separated by a space, here is how:<\/p>\n To list processes by TTY, use the option \u201c-t\u201d followed by the TTY value, as shown:<\/p>\n To show the process tree of the process, use the option \u201c–forest\u201d.<\/p>\n <\/p>\n To print all the threads of a process, use the option \u201c-l\u201d followed by the name of the process as shown:<\/p>\n If you want to list all the format specifiers, use the option \u201cL\u201d<\/p>\n If you want to print the output in your own format, you can use the option \u201c-eo\u201d followed by the format specifier you want. For example, the command \u201cps -eo pid,ppid,user,tty, cmd\u201d will print only the columns PID, PPID, USER, TTY, and CMD<\/p>\n If you want to display the name of a process using its PID, you can use the option \u201c-P\u201d followed by the PID and option \u201c-o\u201d as shown:<\/p>\n If we select a process by its name, it will automatically display its parent and child processes. To do the same make use of the option \u201c-C\u201d.<\/p>\n To check the execution time of a specific command, specify the \u201cetime\u201d format specifier and use the grep command to filter out the process you want. Use the command:<\/p>\n To show security context, use the option \u201c–context\u201d as shown:<\/p>\n In all of the outputs we got till now there are many fields that are being displayed on the screen. Let us take a closer look at each of the fields:<\/p>\n This field displays the User Identifictaiuon number of the user who started this process.<\/p>\n This field displays the process identification number of the process<\/p>\n This field displays the identification number of the parent process, the parent process initiates a process.<\/p>\n This field displays the amount of CPU that this process is currently using.<\/p>\n This field displays the time the process was started on the current system.<\/p>\n This field displays the terminal that was used to start the process.<\/p>\n This field displays the amount of CPU time this process has consumed since it began running.<\/p>\n This field displays the command that was used to start this process.<\/p>\n This field displays the size in physical pages of the core image of the process.<\/p>\n This field displays the resident set size, which is the total amount of non-swapped physical memory used by the process.<\/p>\n This field displays the processor that this process is currently assigned to.<\/p>\n As you have seen, the ps command is a simple command that helps in the task of printing various different pieces of information about processes. You have now learned what the ps command is, why it is used, and the names of the columns on output.<\/p>\n We have also gone technical by looking at the syntax, options, and 20 amazing practical examples of the ps command in the terminal.<\/p>\n","protected":false},"excerpt":{"rendered":" In this article, you will learn all there is to the ps command in Linux-based operating systems. We will go through what the ps command is, why it is used, and the names of...<\/p>\n","protected":false},"author":5,"featured_media":110204,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[35],"tags":[27037],"class_list":["post-110114","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-linux","tag-ps-command-in-linux"],"yoast_head":"\n![\"understanding](\"https:\/\/data-flair.training\/blogs\/wp-content\/uploads\/sites\/2\/2022\/05\/understanding-the-output-of-the-ps-command.webp\")
<\/a><\/p>\n1. PID<\/h4>\n
2. TTY<\/h4>\n
3. TIME<\/h4>\n
4. CMD<\/h4>\n
Options used with the ps command in Linux<\/h3>\n
1. -ax<\/h4>\n
2. -ef<\/h4>\n
3. -u <username><\/h4>\n
5. -C <command><\/h4>\n
6. -p<PID><\/h4>\n
7. -ppid <PPID><\/h4>\n
8. Pstree<\/h4>\n
9. -L<\/h4>\n
10. –sort pmem<\/h4>\n
11. -eo<\/h4>\n
12. -U root -u root<\/h4>\n
Listing all the processes in the current shell<\/h3>\n
<\/a><\/p>\nPrinting all processes in different formats<\/h3>\n
ps -e\u201d or \u201cps -a<\/pre>\n
<\/a><\/p>\nPrinting in BSD format<\/h3>\n
<\/a><\/p>\nPrinting in full format<\/h3>\n
ps -ef<\/pre>\n
<\/a><\/h3>\nDisplaying user running processes in Linux<\/h3>\n
Displaying processes owned by you<\/h4>\n
ps -x<\/pre>\n
<\/a><\/h4>\nDisplaying processes of a specific user<\/h4>\n
ps -u<username><\/pre>\n
<\/a><\/h4>\nPrinting all processes running as root<\/h4>\n
ps -U root -u root<\/pre>\n
<\/a><\/h3>\nDisplaying group processes<\/h3>\n
ps -fG <group name><\/pre>\n
Displaying processes by PID<\/h3>\n
ps -fp <PID><\/pre>\n
<\/a><\/h3>\nDisplaying processes by PPID<\/h3>\n
ps -f--ppid <PPID><\/pre>\n
Displaying multiple processes by PID<\/h3>\n
ps -fp <PID> <PID> <PID><\/pre>\n
<\/a><\/h3>\nDisplaying processes by TTY<\/h3>\n
ps -t <TTY><\/pre>\n
<\/a><\/h3>\nPrinting process tree<\/h3>\n
<\/a><\/p>\nPrinting process threads<\/h3>\n
ps -fl -C <process name><\/pre>\n
<\/a><\/h3>\nListing all format specifiers<\/h3>\n
<\/a><\/p>\nPrinting only specific format specifiers<\/h3>\n
<\/a><\/p>\nFinding a process name using its PID<\/h3>\n
ps -p <PID> -o comm=<\/pre>\n
<\/a><\/h3>\nDisplaying parent and child processes<\/h3>\n
<\/a><\/p>\nChecking the execution time of a process<\/h3>\n
ps -eo comm,etime | grep <process name><\/pre>\n
<\/a><\/h3>\nPrinting security information<\/h3>\n
ps -e --context<\/pre>\n
<\/a><\/h3>\nUnderstanding the output<\/h3>\n
1. UID<\/h4>\n
2. PID<\/h4>\n
3. PPID<\/h4>\n
4. C<\/h4>\n
5. STIME<\/h4>\n
6. TTY<\/h4>\n
7. TIME<\/h4>\n
8. CMD<\/h4>\n
9. SZ<\/h4>\n
10. RSS<\/h4>\n
11. PSR<\/h4>\n
Summary<\/h3>\n