The ps command reports information about the current processes running on a Unix-like system. It is used to monitor, manage, and debug process activity.
Display processes for the current terminal session
Example Usage:
ps
What it does:
Shows a list of processes associated with the current terminal session, including the process ID (PID), terminal, CPU usage, and command name.
Command-line Arguments Explained:
- None: Defaults to showing processes for the current user and terminal session.
Display a detailed list of all processes
Example Usage:
ps aux
What it does:
Provides a comprehensive list of all running processes, including user, CPU, memory, and command-line details.
Command-line Arguments Explained:
a: Displays processes for all users.u: Shows user-oriented format with detailed resource usage.x: Includes processes without a controlling terminal (background processes).
Example Usage:
ps -ef
What it does:
Lists all processes in a detailed format, including the user, PID, parent PID, CPU usage, and command.
Command-line Arguments Explained:
-e: Selects all processes.-f: Displays the full format listing (long format).
Display processes by PID
Example Usage:
ps -p [PID]
What it does:
Shows information about a specific process using its process ID (PID).
Command-line Arguments Explained:
-p: Specifies the process ID to monitor.
Example Usage:
ps -l
What it does:
Shows process details in a long format, including PID, PPID, command, and resource usage.
Command-line Arguments Explained:
-l: Enables long (detailed) listing format.
Display processes with custom output fields
Example Usage:
ps -o [field1],[field2]
What it does:
Customizes the output to display only specified fields, such as PID, command, or memory usage.
Command-line Arguments Explained:
-o: Defines custom output fields. Replace [field1],[field2] with desired fields like pid,comm,mem.
Sort processes by CPU usage
Example Usage:
ps -eo %cpu,comm --sort -%cpu
What it does:
Lists processes sorted by CPU usage in descending order, highlighting the most resource-intensive tasks.
Command-line Arguments Explained:
-e: Selects all processes.-o: Specifies output fields, e.g., %cpu (CPU percentage) and comm (command name).--sort: Sorts the output by the specified field ( - denotes descending order).
Display processes owned by a specific user
Example Usage:
ps -u [username]
What it does:
Lists processes owned by the specified user, showing their resource usage and command details.
Command-line Arguments Explained:
-u: Displays processes for the given username. If no username is provided, it defaults to the current user.
Display process tree structure
Example Usage:
ps --forest
What it does:
Generates a tree-like view of processes, showing parent-child relationships.
Command-line Arguments Explained:
--forest: Displays processes in a hierarchical tree format, with indentation for child processes.
Display threads of a specific process
Example Usage:
ps -T -p [PID]
What it does:
Lists all threads associated with the specified process, including thread IDs (TID) and related details.
Command-line Arguments Explained:
-T: Shows threads instead of processes.-p: Specifies the process ID to monitor.
Display processes with their start time and command line
Example Usage:
ps -eo pid,etime,cmd
What it does:
Shows the PID, elapsed time, and full command line for all processes.
Command-line Arguments Explained:
-e: Selects all processes.-o: Customizes output to include pid (process ID), etime (elapsed time), and cmd (command line).
Filter processes by command name
Example Usage:
ps -C [command_name]
What it does:
Displays processes matching the specified command name, such as nginx or bash.
Command-line Arguments Explained:
-C: Filters processes by the exact command name provided. Use --help to view supported options.
