Loop Through Variables in bash and change their content [duplicate] - bash

Question

This question already has answers here:
Indirect variable assignment in bash
(7 answers)
Iterating over variable name in bash script
(2 answers)
What is indirect expansion? What does ${!var*} mean?
(6 answers)
Closed 5 months ago.
How can I make this into a loop? I have trouble with looping through variables.
WSTATUS="exited" //example output from command
VSTATUS="running"
NSTATUS="running"
JSTATUS="running"
if [[ $WSTATUS == run* ]]; then
WSTATUS=${GREEN}$WSTATUS
else
WSTATUS=${RED}$WSTATUS
fi
if [[ $VSTATUS == run* ]]; then
VSTATUS=${GREEN}$VSTATUS
else
VSTATUS=${RED}$VSTATUS
fi
if [[ $NSTATUS == run* ]]; then
NSTATUS=${GREEN}$NSTATUS
else
NSTATUS=${RED}$NSTATUS
fi
if [[ $JSTATUS == run* ]]; then
JSTATUS=${GREEN}$JSTATUS
else
JSTATUS=${RED}$JSTATUS
fi
I have tried this:
...varibles
array=( $WSTATUS $VSTATUS $NSTATUS $JSTATUS )
for value in "${array[#]}"
do
if [[ $value == run* ]]; then
WSTATUS=${GREEN}$value
else
WSTATUS=${RED}$value
fi
done
How can i iterate through bash variables, not their content?
changing this wstatus into value does not work --> WSTATUS=${GREEN}$value

Answer 1

Not a loop, but a function already helps a lot:
colorme() {
if [[ "$1" == run* ]]; then
printf '%s' "${GREEN}$1"
else
printf '%s' "${RED}$1"
fi
}
WSTATUS=$(colorme "$WSTATUS")
VSTATUS=$(colorme "$VSTATUS")
NSTATUS=$(colorme "$NSTATUS")
JSTATUS=$(colorme "$JSTATUS")

Answer 2

You can use nameref (declare -n var in following script)
#!/usr/bin/env bash
GREEN=GREEN
RED=RED
WSTATUS="exited"
VSTATUS="running"
NSTATUS="running"
JSTATUS="running"
array=( WSTATUS VSTATUS NSTATUS JSTATUS )
declare -n var
for var in "${array[#]}"
do
[[ $var == run* ]] && prefix="${GREEN}" || prefix="${RED}"
var="$prefix$var"
done
declare -p WSTATUS VSTATUS NSTATUS JSTATUS

Answer 3

What you are looking for is declare and ! expansion
a=b
declare $b=12
echo $b
=>
12
That is for setting a variable whose name is computed (here from another variable)
echo ${!a}
=>
12
That is for accessing the content of a variable whose name is stored in another variable
So in your case, it may look like
WSTATUS="exited" //example output from command
VSTATUS="running"
NSTATUS="running"
JSTATUS="running"
totest=( WSTATUS VSTATUS NSTATUS JSTATUS )
for name in ${array[#]}
do
if [[ ${!name} == run* ]]; then
declare $name=${GREEN}${!name}
else
declare $name=${RED}${!name}
fi
done
Copying without any other modification your script. I have some reservation about the idea to add those, apparently green and red escape code to the variable content, rather than taking this decision at print time. I didn't really try do understand nor the test neither the action your script is taking. Even, (XY problem parenthesis) the fact that what you need is to loop through variable is questionable. knittl solution, tho it does not answer to your question, is probably a better solution to your real problem.
But well, your question was how to loop through variable. This is a way to do it.