Master Linux Process Management: ps, top, htop, and kill Commands Explained

1. Process Viewing and Management Tools

ps command : reports a snapshot of current processes.

Common options:

-A or -e: show all processes

-a: all processes not associated with a terminal

-u: processes owned by a specific user

-x: include processes without a controlling terminal (often used with -a or -u)

-f: full‑format listing

Typical combinations: ps -ef – full information for all processes ps -efH – display process hierarchy ps -aux – all processes with detailed info ps -axo pid,command,psr,pri,ni – custom columns (PID, command, processor, priority, nice)

Command demonstration :

2. top Command

top dynamically displays Linux task information.

Key fields in the header line:

UID/PID/PPID – user, process ID, parent process ID

C – CPU usage percentage

STIME – process start time

TTY – controlling terminal

TIME – cumulative CPU time

CMD – command name

Common column headings:

USER, PID, %CPU, %MEM, VSZ, RSS, TTY, STAT, START, TIME, COMMAND

STAT values:

R – running

S – interruptible sleep

D – uninterruptible sleep

T – stopped

Z – zombie

Interactive options (press the corresponding key while top is running):

P – sort by CPU usage

M – sort by memory usage

T – sort by running time

l – toggle load average line

t – toggle task summary

1 – show per‑CPU statistics

m – toggle memory information

q – quit

s – change refresh delay

k – kill a process

3. htop Command

htop is an interactive process viewer.

Basic usage: htop – launch the viewer

Key shortcuts:

u – filter by user

l – show files opened by the highlighted process

s – display system calls of the highlighted process

a – bind a process to a specific CPU

# – jump to the process with the given PID

Supported options:

-d – set delay

-u USERNAME – show only processes of USERNAME

-s COLUMN – sort by the specified column

4. Linux Process and Job Management

Process management involves sending signals to control processes, typically using the kill command.

Useful commands: kill -l – list all available signals kill -s SIGNAL PID – send a specific signal killall PROCESS_NAME – terminate all processes with the given name

Common signals:

SIGHUP (1) – reload configuration

SIGINT (2) – interrupt (Ctrl+C)

SIGKILL (9) – force kill

SIGTERM (15) – graceful termination

SIGSTOP (19) – stop process

Job control allows moving jobs between foreground and background.

Typical commands:

Ctrl+Z – suspend the current job command & – run a command in the background

fg %JOBNUM – bring a background job to the foreground

bg %JOBNUM – resume a stopped job in the background

kill %JOBNUM – terminate a specific job

Author: 小耳朵 – Source: purify.blog.51cto.com