I did the following from a bash shell.
export myPath="/home/user/dir"
Then I verified the value of this by 'echo'ing this value from both shell and a inside a bash script. Both worked fine.
Then I tried setting the value of this variable from inside a script like this.
myPath="/home/user/newdir"
and tried printing this variable from shell. I thought the variable will hold the updated value, but it was showing the old value.
How can I update the value from a script? I am looking to do it without using source if possible.
To make the variables persist after the script finishes, you have to run it using the source command:
When a script is run using source it runs within the existing shell, any variables created or modified by the script will remain available after the script completes. In contrast if the script is run just as filename, then a separate subshell (with a completely separate set of variables) would be spawned to run the script.
Related
I'm trying to make variables exits outside of a shell script without using source.
The variables are declared in shell script with
export varA=3
and I run the script with ./filename.sh
I want
echo $varA
in the terminal to return 3 (i.e. the value of varA). So extend the scope of the variable to outside of the script
To sum up: how do I make the variables inside a shell script exist outside.
Thank you in advance
You can run your script on this way:
. ./filename.sh
This mean when run it will not spawn new shell but run it in current. And variables you set in your script will be available in your shell. This is kind of "source" as mentioned in comments.
I'm trying to run a zsh/bash script that writes several values to environment variables, I want these variables available to the parent shell as they are required for several tools we use. If I manually run the script using '. myscript myparamater' I get the expected result, however defining a zsh function to do this without having to use dot notation does not result in the variables being set.
I'm pretty new to zsh/bash scripting, and this has been my first real effort at writing something useful. I am running this on MacOS but would like for it to work in Linux as well, the script my function is sourcing is doing some bash logic and in some cases also executing a third-party executable (really a bash script that calls a java binary). In my script I'm calling the third-party tool directly using its executable name, calling it using exec or dot notation does not seem to work properly.
zsh Function:
function okta-auth {
. okta_setprofile $1
}
My script:
https://gist.github.com/ckizziar/a60a84a6a148a8fd7b0ef536409352d3
Using '. okta_setprofile myprofile' I receive the expected output of the okta_setprofile script, four environment variables (AWS_ACCESS_KEY_ID, AWS_SECRET_ACCESS_KEY, AWS_DEFAULT_REGION, and AWS_SESSION_TOKEN) are set in my shell.
Using 'okta-auth myprofile' the script feedback is the same as previously, however after execution, the environment variables are not set or updated.
Updated 20190206 to show flow
okta_setprofile flow diagam
I have a file run_me
#!/bin/bash
export BOBO=MOMO
After I run run_me, the variable BOBO isn't set. Why? How can it be fixed?
You need to source it:
. ./run_me
OR
source ./run_me
In order to run this script in current shell otherwise BASH creates a new sub-shell and executes the script in that sub-shell therefore all the changes (variable etc) are not reflected in the current parent shell.
I have a simple bash script:
#!/bin/bash
JAVA_HOME=/usr
EC2_HOME=~/ec2-api
echo $EC2_HOME
export PATH=$PATH:$EC2_HOME/bin
I run the script like so
$ ./ec2
/Users/user/ec2-api
The script runs and produces the correct output.
However, when I now try to access the EC2_HOME variable, I get nothing out:
$ echo $EC2_HOME
I get a blank string back. What am I doing wrong?
Do either of the following instead:
source ec2
or
. ec2
(note the . notation is just a shortcut for source)
Explanation:
This is because ./ec2 actually spawns a subshell from your current shell to execute the script, and subshells cannot affect the environment of the parent shell from which it spawned.
Thus, EC2_HOME does get set to /Users/user/ec2-api correctly in the subshell (and similarly the PATH environment variable is updated and exported correctly in the subshell as well), but those changes won't propagate back to your parent shell.
Using source runs the script directly in the current shell without spawning a subshell, so the changes made will persist.
(A note on export: export is used to tell new shells spawned from the current shell to use the variables exported from the current shell. So for any variables you would only use in the current shell, they need not be exported.)
A shell script can never modify the environment of their parent.
To fix your problem, you can use the dot (.) command:
$ . ./ec2
and that should work. In cshell, it would be
% source ./ec2
To learn more about shells and scripts, my best resource is by far Unix power tools.
I have some proxy settings that I only occasionally want to turn on, so I don't want to put them in my ~/.bash_profile. I tried putting them directly in ~/bin/set_proxy_env.sh, adding ~/bin to my PATH, and chmod +xing the script but though the script runs, the variables don't stick in my shell. Does anyone know how to get them to stick around for the rest of the shell session?
Use one of:
source <file>
. <file>
In the script use
export varname=value
and also execute the script with:
source set_proxy_env.sh.
The export keyword ensures the variable is marked for automatic inclusion in the environment of subsequently executed commands. Using source to execute a script starts it with the present shell instead of launching a temporary one for the script.
Did you try this:
. ~/bin/set_proxy_env.sh
Running it by itself opens a separate subshell (I think) and sets the variable there. But then the binding is lost after exiting back into your shell. The dot at the front tells it to run it within the same shell.
Also, don't forget to export the variables you need like so: export MYVAR=value