convert comma separated command line arguments to json in shell script - linux

Question

I'm using below script to generate json data from comma separated values to feed zabbix.
but i'm getting one extra comma symbol. please try to optimize the comma in the end line.
#/bin/bash
IFS=':, ' read -r -a array <<< "$1"
idx=0
echo {\"data\":[
while [ -n "${array[$idx]}" ]; do
echo -n \{\"{#R_IP}\":\""${array[$idx]}"\"}
let idx=$idx+1
[ -n "$array[idx]}" ] && echo "," || echo
done
echo ]}
exit
input
./test.sh embimsrv.exe,emcms.exe,emcmsg.exe,emforecastsrv.exe,emgtw.exe,emguisrv.exe,emmaintag.exe,emselfservicesrv.exe,Naming_Service.exe,p_ctmce.exe,p_ctmcs.exe,p_ctmrt.exe,p_ctmtr.exe,p_ctmwd.exe
output
{"data":[
{"{#R_IP}":"embimsrv.exe"},
{"{#R_IP}":"emcms.exe"},
{"{#R_IP}":"emcmsg.exe"},
{"{#R_IP}":"emforecastsrv.exe"},
{"{#R_IP}":"emgtw.exe"},
{"{#R_IP}":"emguisrv.exe"},
{"{#R_IP}":"emmaintag.exe"},
{"{#R_IP}":"emselfservicesrv.exe"},
{"{#R_IP}":"Naming_Service.exe"},
{"{#R_IP}":"p_ctmce.exe"},
{"{#R_IP}":"p_ctmcs.exe"},
{"{#R_IP}":"p_ctmrt.exe"},
{"{#R_IP}":"p_ctmtr.exe"},
{"{#R_IP}":"p_ctmwd.exe"},
]}

Answer 1

Use a proper tool, like jq, to generate your JSON.
printf '%s' "$1" | jq -R 'split(",") | map({"{#R_IP}": .}) | {data: .}'

Answer 2

Manually piecing together JSON like this is pretty brittle. But here goes. A very common trick is to prefix each string except the first with a comma.
#!/bin/bash
IFS=':, ' read -r -a array <<< "$1"
prefix=''
printf '%s' '{"data":['
for item in "${array[#]}"; do
printf '%s%s' "$prefix" "{\"{#R_IP}\":\"$item\"}"
prefix=','
done
printf '%s\n' ']}'
Notice also how no explicit exit is required at the end of a script. The shell stops executing the script and terminates when it reaches the end of the script.
Also, the shebang needs to start with exactly the two single-byte characters #!.
Finally, a much better overall design is probably to not require the arguments to be comma-separated; but I won't try to fix that here.