"env" Command

Learn all about env command

HOME

env - run a program in a modified environment

root:~# man env

env is considered as program itself.

Example-1

1.1 Default Output - View all environment variables

When no command is given then env prints the default variables available in environment.

root@:~# env
SSH_AGENT_PID=6155
TERM=xterm-256color
SHELL=/bin/bash
HISTSIZE=1000
HISTFILESIZE=1000
USER=root

Example-2

2.1 Modify Default Parameter

root@:~# date
Sat Jan 13 09:43:05 UTC 2018
root@:~# env TZ=MST7MDT date
Sat Jan 13 02:43:12 MST 2018

Example-3

3.1 Start with Empty Environment (-i)

Execute the utility with only those environment variables specified by name=value options. The environment inherited by env is ignored completely.

root@:~# env -i env
root@:~#
root@:~# env -i USER=PARTH env
USER=PARTH
root@:~#

3.2 Modify Existing Environment

root@:~# env
SSH_AGENT_PID=6155
TERM=xterm-256color
SHELL=/bin/bash
HISTSIZE=1000
HISTFILESIZE=1000
USER=root
root@:~#env USER=PARTH env
SSH_AGENT_PID=6155
TERM=xterm-256color
SHELL=/bin/bash
HISTSIZE=1000
HISTFILESIZE=1000
USER=PARTH