How to Understand the 'ps' Command output in Linux

You can get process details by using the ps command. Those are number of processes running in a current Session, and other parameters about the process.  

Here is all about how to use ps command in Linux.


The ps command


How to use ps command



Here's an example that is how it appears when you issue the 'ps' command.

  • PID (Process Id) - It is the process identification number.
  • TTY(Terminal name) - associated with this process
  • TIME(Time) - the format is hh: mm: ss (Hours, Minutes, and Seconds). Cumulated time of that particular process.
  • CMD (Executable Command name). You May Also Like: PS Command Options in Linux

How to understand slave/master terminal

Here is all about Slave and Master terminal.
  • The pts/0 is the slave terminal. The pts means pseudo terminal slave. Raise your knowledge by bringing in these quick definitions. LINUX - DIFFERENCE BETWEEN TTY AND PTS.
  • In reality, the terminals are two types. One is ptmx (Master) and pts (Slave).
  • The master terminal holds the details of slaves. Those are pts/0, pts/1, and so on.
  • The slave numbers start from 0, 1, 2, 3...
  • The Psuedo terminals ( Master and Slave) are present in the/dev directory.

How to Locate Master/Slave Terminals




On top of that, pseudo terminals are two types. BSD style and UNIX98 style. The UNIX98 is the newest style. BSD-style pseudoterminals vs. UNIX 98 pseudoterminals.

How to use ps -eF command




The Output of ps -eF

  • UID (user id)-it is a root user
  • PID (Process Id)
  • PID (Parent process id)
  • C (Processer utilization). Currently, it is '0'.
  • SZ (size)
  • RSS (Resident set size). Non-swapped physical memory.
  • PSR (Processor number to which this process is assigned)
  • STIME (Start Time)
  • TTY (see the above)
  • TIME (Cumulative CPU time)
  • CMD (The executable command details). Here, I have issued ps -eF. You can see this command in the above picture.


How to get count of processes

Here's the command to use quickly.

$ ps | wc -l
4


References

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