Menu
I'm trying to set a git hash value into an environment variable, i thought it would be as simple as doing this:
git log --oneline -1 | export GIT_HASH=$1 But the $1 doesn't contain anything. What am I doing wrong?
437
To store the output of a command in a variable, you can use the shell command substitution feature in the forms below: variable_name=$(command) variable_name=$(command [option ...] arg1 arg2 ...) OR variable_name='command' variable_name='command [option ...]
To export a environment variable you run the export command while setting the variable. We can view a complete list of exported environment variables by running the export command without any arguments. To view all exported variables in the current shell you use the -p flag with export.
The most used command to displays the environment variables is printenv . If the name of the variable is passed as an argument to the command, only the value of that variable is displayed. If no argument is specified, printenv prints a list of all environment variables, one variable per line.
$1 is used to access the first argument in a script or a function. It is not used to access output from an earlier command in a pipeline.
You can use command substitution to get the output of the git command into an environment variable like this:
export GIT_HASH=`git log --oneline -1` However...
This answer is specially in response to the question regarding the Bourne Shell and it is the most widely supported. Your shell (e.g. GNU Bash) will most likely support the $() syntax and so you should also consider Michael Rush's answer.
But some shells, like tcsh, do not support the $() syntax and so if you're writing a shell script to be as bulletproof as possible for the greatest number of systems then you should use the `` syntax despite the limitations.
131
If you love us? You can donate to us via Paypal or buy me a coffee so we can maintain and grow! Thank you!
Donate Us With
