Ps

Internal

• Linux
• /proc/meminfo

Overview

ps gets its information from /proc/<pid>/stat files.

Installation

Ubuntu

apt-get install -y procps

Options

-A, -e

Select all processes. -A and -e are identical.

-f

Full-format listing.

-L

Show threads.

The thread ID is listed under the "LWP" column.

--forest

Hierarchical display of the process tree.

--no-headers

Skips the display of the header line. Useful when counting lines in the ps output with wc -l.

-l

Displays the process state (S) and, if sleeping, what kernel channel it is waiting on (WCHAN).

Generic Attributes

Any process attribute can be obtained with

ps <pid> -o <format>

where <format> is the attribute label.

Columns

LWP

The thread ID.

NLWP

The number of threads for the process.

S

The process state.

WCHAN

If the process is sleeping, shows the kernel channel the process is waiting on.

TTY

The TTY device character device file, relative to /dev.

SESS

The process' session ID.