Remove null variables while echoing in a single string

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I have the below condition where values are as below.
```
emp_name="Sid"
emp_id=1234
emp_hobby=""
emp_likes="swimming"
emp_dislikes=""

emp_summary="emp_name:$emp_name,emp_id:$emp_id,emp_hobby:$emp_hobby,emp_likes:$emp_likes,emp_dislikes:$emp_dislikes"
```

if I echo above with the values that are provided as an example it will give result as

`"emp_name:"Sid",emp_id:1234,emp_hobby:,empf_likes:"swimming",emp_dislikes:"`

I need help with a dynamic code where if any of the value is null that complete variable is removed from the echo as below

`"emp_name:"Sid",emp_id:1234,emp_likes:"swimming"`

i tried {parameter:+word} returns the values but not sure how to deal with the variable name itself.

What I have tried:

i tried {parameter:+word} returns the values but not sure how to deal with the variable name itself.

Posted 10-Oct-21 20:30pm

Shreyansh Shukla 2021

Updated 17-Jul-23 21:55pm

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Member 10601191 · Answer 1 · 2023-07-17T21:55:00

Shell

cat script #bash script

emp_name="Sid"
emp_id=1234
emp_hobby=""
emp_likes="swimming"
emp_dislikes=""

emp_summary=""
summary=""

 #
 # if the names are not known ..._ 
 # then use something like
 #      for var in $(compgen -v|grep ^emp_)

for var in emp_name emp_id emp_hobby emp_likes emp_dislikes
do
	# use indirect variable' capability of bash - aka namerefs
	declare -n namref=$var;
	
	[ "" != "$namref" ] && summary+="${!namref}:$namref,"
done

emp_summary="${summary/%,/}" #trim the last comma off the final result

echo "emp_summary:${emp_summary}"

 #test run
./script 
emp_summary:emp_name:Sid,emp_id:1234,emp_likes:swimming