i have a shell script "script.sh" which gives output as "success" or "Failed" when i execute in unix window.
Now i want to store the output of script.sh into a unix command variable. say $a = {output of script.sh}
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Pretty much the same as redirect command output into variable and standard output in kshDan Dascalescu– Dan Dascalescu2014-04-03 07:48:42 +00:00Commented Apr 3, 2014 at 7:48
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5 Answers
Two simple examples to capture output the pwd command:
$ b=$(pwd)
$ echo $b
/home/user1
or
$ a=`pwd`
$ echo $a
/home/user1
The first way is preferred. Note that there can't be any spaces after the = for this to work.
Example using a short script:
#!/bin/bash
echo "hi there"
then:
$ ./so.sh
hi there
$ a=$(so.sh)
$ echo $a
hi there
In general a more flexible approach would be to return an exit value from the command and use it for further processing, though sometimes we just may want to capture the simple output from a command.
Suppose you want to store the result of an echo command
echo hello
x=$(echo hello)
echo "$x",world!
output:
hello
hello,world!
1 Comment
jean
@NitsanBaleli This is a answer, not a question
You should probably re-write the script to return a value rather than output it. Instead of:
a=$( script.sh ) # Now a is a string, either "success" or "Failed"
case "$a" in
success) echo script succeeded;;
Failed) echo script failed;;
esac
you would be able to do:
if script.sh > /dev/null; then
echo script succeeded
else
echo script failed
fi
It is much simpler for other programs to work with you script if they do not have to parse the output. This is a simple change to make. Just exit 0 instead of printing success, and exit 1 instead of printing Failed. Of course, you can also print those values as well as exiting with a reasonable return value, so that wrapper scripts have flexibility in how they work with the script.
export a=$(script.sh)
Hope this helps. Note there are no spaces between variable and =. To echo the output
echo $a
5 Comments
logan
when the script will execute ? after submitting echo $a? or after export ?
Sven Marnach
Why are you exporting
a? You should use double quotes around $a in the echo statement.
Jeffrey Vandenborne
@login it will run the script in a subshell and wait for it until it quits, that subshell's streams will be pointing to the variable "a", meaning that everything they output will be written to the variable instead of the standard output of your main shell
gandalf007
@SvenMarnach I didn't know how the OP wanted to use the variable, exporting makes it available to child processes
gandalf007
@logan $(command) is a way to run commands and capture output
You need to start the script with a preceding dot, this will put the exported variables in the current environment.
#!/bin/bash
...
export output="SUCCESS"
Then execute it like so
chmod +x /tmp/test.sh
. /tmp/test.sh
When you need the entire output and not just a single value, just put the output in a variable like the other answers indicate
1 Comment
Charles Duffy
No reason for "export" when using source. Also, for only a single value, exit status or stdout seem that they would make more sense.