I have a pretty simple script that is something like the following:
#!/bin/bash VAR1="$1" MOREF='sudo run command against $VAR1 | grep name | cut -c7-' echo $MOREF
When I run this script from the command line and pass it the arguments, I am not getting any output. However, when I run the commands contained within the $MOREF
variable, I am able to get output.
How can one take the results of a command that needs to be run within a script, save it to a variable, and then output that variable on the screen?
To store the output of a command in a variable, you can use the shell command substitution feature in the forms below: variable_name=$(command) variable_name=$(command [option ...] arg1 arg2 ...) OR variable_name='command' variable_name='command [option ...] arg1 arg2 ...'
Here are the different ways to store the output of a command in shell script. You can also use these commands on terminal to store command outputs in shell variables. variable_name=$(command) variable_name=$(command [option ...] arg1 arg2 ...) OR variable_name=`command` variable_name=`command [option ...]
We can set variables for a single command using this syntax: VAR1=VALUE1 VAR2=VALUE2 ... Command ARG1 ARG2...
In addition to backticks `command`
, command substitution can be done with $(command)
or "$(command)"
, which I find easier to read, and allows for nesting.
OUTPUT=$(ls -1) echo "${OUTPUT}" MULTILINE=$(ls \ -1) echo "${MULTILINE}"
Quoting ("
) does matter to preserve multi-line variable values; it is optional on the right-hand side of an assignment, as word splitting is not performed, so OUTPUT=$(ls -1)
would work fine.
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