Unix & Linux Stack Exchange is a question and answer site for users of Linux, FreeBSD and other Un*x-like operating systems. Join them; it only takes a minute:

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

I have several projects that require me to change versions of Java/Grails/Maven. I'm trying to handle this with some scripts that would make the changes. For example:


export JAVA_HOME=/cygdrive/c/dev/Java/jdk1.5.0_22
export PATH=$JAVA_HOME/bin:$PATH
export GRAILS_HOME=/cygdrive/c/dev/grails-1.0.3
export MAVEN_HOME=/cygdrive/c/dev/apache-maven-2.0.11
which java
which grails
which mvn

When this executes, it successfully changes the PATH within the context of the script, but then the script ends, and no change has been accomplished.

How can I run a script in a way to change the PATH in for the shell in which I am currently working?

I'm using Cygwin.

share|improve this question
up vote 17 down vote accepted

You have to use source or eval or to spawn a new shell.

When you run a shell script a new child shell is spawned. This child shell will execute the script commands. The father shell environment will remain untouched by anything happens in the child shell.

There are a lot of different techniques to manage this situation:

  1. Prepare a file sourcefile containg a list of commands to source in the current shell:

    export JAVA_HOME=/cygdrive/c/dev/Java/jdk1.5.0_22
    export PATH=$JAVA_HOME/bin:$PATH

    and then source it

    source sourcefile

    note that there is no need for a sha-bang at the begin of the sourcefile, but it will work with it.

  2. Prepare a script evalfile.sh that prints the command to set the environment:

    echo "export JAVA_HOME=/cygdrive/c/dev/Java/jdk1.5.0_22"
    echo "export PATH=$JAVA_HOME/bin:$PATH"

    and then evaluate it:

    eval `evalfile.sh`
  3. Configure and run a new shell:

    export JAVA_HOME=/cygdrive/c/dev/Java/jdk1.5.0_22
    export PATH=$JAVA_HOME/bin:$PATH
    exec /bin/bash

    note that when you type exit in this shell, you will return to the father one.

  4. Put an alias in your ~/.bashrc:

    alias prepare_environ='export JAVA_HOME=/cygdrive/c/dev/Java/jdk1.5.0_22; export PATH=$JAVA_HOME/bin:$PATH;'

    and call it when needed:

share|improve this answer
+1 for the new shell.. i like that. – amyassin Oct 28 '11 at 2:32
I noticed that source works only for bash. Output for ksh: /bin/ksh: source: not found, for sh: sh: 0: source: not found. The answer below should be considered for these shells. – Danny Lo Apr 8 '15 at 9:19
@dannylo, you are right but the question is clearly bash centric. – andcoz Apr 8 '15 at 13:29

You could do that by using the source builtin:

. script_name

Some shells provide an alias named source:

source script_name
share|improve this answer

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.