MyTetra Share
Делитесь знаниями!
List All Environment Variables Command
Время создания: 27.03.2017 10:02
Текстовые метки: linux variable environment global
Раздел: Linux

You can use any one of the following command to display the environment variables and their values.

a) printenv command – Print all or part of environment.

b) env command – Print all exported environment or run a program in a modified environment.

c) set command – Print the name and value of each shell variable.

Examples

I recommend that you use the printenv command:


printenv

OR


printenv | less

OR


printenv | more

Sample outputs:

Fig.01: Command to see a list of all currently defined environment variables in a Linux bash terminal

A list of the commonly used variables in Linux

System Variable

Meaning

To View Variable Value Type

BASH_VERSION

Holds the version of this instance of bash.

echo $BASH_VERSION

HOSTNAME

The name of the your computer.

echo $HOSTNAME

CDPATH

The search path for the cd command.

echo $CDPATH

HISTFILE

The name of the file in which command history is saved.

echo $HISTFILE

HISTFILESIZE

The maximum number of lines contained in the history file.

echo $HISTFILESIZE

HISTSIZE

The number of commands to remember in the command history. The default value is 500.

echo $HISTSIZE

HOME

The home directory of the current user.

echo $HOME

IFS

The Internal Field Separator that is used for word splitting after expansion and to split lines into words with
the read builtin command. The default value is <space><tab><newline>.

echo $IFS

LANG

Used to determine the locale category for any category not specifically selected with a variable starting with LC_.

echo $LANG

PATH

The search path for commands. It is a colon-separated list of directories in which the shell looks for commands.

echo $PATH

PS1

Your prompt settings.

echo $PS1

TMOUT

The default timeout for the read builtin command. Also in an interactive shell, the value is interpreted as
the number of seconds to wait for input after issuing the command. If not input provided it will logout user.

echo $TMOUT

TERM

Your login terminal type.

echo $TERM
export TERM=vt100

SHELL

Set path to login shell.

echo $SHELL

DISPLAY

Set X display name

echo $DISPLAY
export DISPLAY=:0.1

EDITOR

Set name of default text editor.

export EDITOR=/usr/bin/vim

set and env command

You can use the env / set command too:


env

env | more

set

set | more

Sample outputs:

HOME=/home/vivek

vivek@nas01:~$ env

TERM=xterm-256color

SHELL=/bin/bash

XDG_SESSION_COOKIE=9ee90112ba2cb349f07bfe2f00002e46-1381581541.324726-906214463

SSH_CLIENT=192.168.1.6 60190 22

SSH_TTY=/dev/pts/1

USER=vivek

MAIL=/var/mail/vivek

PATH=/usr/local/bin:/usr/bin:/bin:/usr/local/games:/usr/games

PWD=/home/vivek

LANG=en_IN

SHLVL=1

HOME=/home/vivek

LANGUAGE=en_IN:en

LOGNAME=vivek

SSH_CONNECTION=192.168.1.6 60190 192.168.1.10 22

_=/usr/bin/env

A note about env/set command

The env will only display a list of environment variables that have been exported and it will not show all bash variables. The set command allows you to change the values of shell options and set the positional parameters, or to display the names and values of shell variables. If no options or arguments are supplied, set displays the names and values of all shell variables and functions, sorted according to the current locale, in a format that may be reused as input for setting or resetting the currently-set variables. Hence, I recommend that you use printenv command to dump the list of all shell variables on screen. To save the list of all shell environment variables to a file, enter:


printenv > env.txt

cat env.txt

Use the grep command to search for particular variable:


printenv | grep foo

printenv | grep HOME

Так же в этом разделе:
 
MyTetra Share v.0.53
Яндекс индекс цитирования