Reload Environment Variables in a Bash Script

Question

How can I reload the environment variables in a Bash Script. I am updating ~/.bashrc in the same script and want the changes to get reflected.

I have tried using

source ~/.bashrc

The following is my script

#!/bin/bash
echo $PATH 
echo "export PATH=\$PATH:/home/user/test" >> ~/.bashrc
source ~/.bashrc
echo $PATH

Both the echos return the same value of $PATH. But when I run echo $PATH on another instance of bash it returns the newly added path.

Any help would be appreciated.

Thanks.

The following is the content of my .bashrc file (without the modifications from the script)

# ~/.bashrc: executed by bash(1) for non-login shells.
# see /usr/share/doc/bash/examples/startup-files (in the package bash-doc)
# for examples

# If not running interactively, don't do anything

[ -z "$PS1" ] && return

HISTCONTROL=ignoredups:ignorespace

shopt -s histappend

HISTSIZE=1000
HISTFILESIZE=2000

shopt -s checkwinsize

[ -x /usr/bin/lesspipe ] && eval "$(SHELL=/bin/sh lesspipe)"

if [ -z "$debian_chroot" ] && [ -r /etc/debian_chroot ]; then
    debian_chroot=$(cat /etc/debian_chroot)
fi

case "$TERM" in
    xterm-color) color_prompt=yes;;
esac

if [ -n "$force_color_prompt" ]; then
    if [ -x /usr/bin/tput ] && tput setaf 1 >&/dev/null; then
  color_prompt=yes
    else
  color_prompt=
    fi
fi

if [ "$color_prompt" = yes ]; then
    PS1='${debian_chroot:+($debian_chroot)}\[\033[01;32m\]\u@\h\[\033[00m\]:\[\033[01;34m\]\w\[\033[00m\]\$ '
else
    PS1='${debian_chroot:+($debian_chroot)}\u@\h:\w\$ '
fi
unset color_prompt force_color_prompt

case "$TERM" in
xterm*|rxvt*)
    PS1="\[\e]0;${debian_chroot:+($debian_chroot)}\u@\h: \w\a\]$PS1"
    ;;
*)
    ;;
esac

if [ -x /usr/bin/dircolors ]; then
    test -r ~/.dircolors && eval "$(dircolors -b ~/.dircolors)" || eval "$(dircolors -b)"
    alias ls='ls --color=auto'
    #alias dir='dir --color=auto'
    #alias vdir='vdir --color=auto'

    alias grep='grep --color=auto'
    alias fgrep='fgrep --color=auto'
    alias egrep='egrep --color=auto'
fi

alias ll='ls -alF'
alias la='ls -A'
alias l='ls -CF'

if [ -f ~/.bash_aliases ]; then
    . ~/.bash_aliases
fi

if [ -f /etc/bash_completion ] && ! shopt -oq posix; then
    . /etc/bash_completion
fi

Does your .bashrc run to the end, or is there an early exit? You should show the contents of this file. — BMitch
– BMitch, Commented Feb 20, 2011 at 4:14
I don't see the /home/user/test line at the bottom of this script, is there an error appending to the file, e.g. write permission? — BMitch
– BMitch, Commented Feb 20, 2011 at 11:57

Community · Accepted Answer · 2017-05-23 10:24:25Z

4

Your .bashrc starts:

# If not running interactively, don't do anything
[ -z "$PS1" ] && return

Since your script does not have PS1 set (because it is not interactive), it doesn't reset path because it exits early - exactly as B Mitch suggested. To demonstrate, modify your script:

#!/bin/bash
echo $PATH 
echo "export PATH=\$PATH:/home/user/test" >> ~/.bashrc
PS1='$ '
source ~/.bashrc
echo $PATH

edited May 23, 2017 at 10:24

CommunityBot

11 silver badge

answered Feb 20, 2011 at 12:43

Jonathan Leffler

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