I am trying to return a value from one script to another. However, in the child script there are multiple echos, so am not sure how to retrieve a specific one in the parent scrip as if I try to do return_val = $(./script.sh) then return_val will have multiple arguments. Any solution here?
script 1:
status=$(script2.sh)
if [ $status == "hi" ]; then
echo "success"
fi
script 2:
echo "blah"
status="hi"
echo $status
Solution 1) for this specific case, you could get the last line that was printed by the script 2, using the tail -1 command. Like this:
script1.sh
#!/bin/bash
status=$( ./script2.sh | tail -1 )
if [ $status == "hi" ]; then
echo "success"
fi
script2.sh
#!/bin/bash
echo "blah"
status="hi"
echo $status
The restriction is that it will only work for the cases where you need to check the last string printed by the called script.
Solution 2) If the previous solution doesn't apply for your case, you could also use an identifier and prefix the specific string that you want to check with that. Like you can see below:
script1.sh
#!/bin/bash
status=$( ./script2.sh | grep "^IDENTIFIER: " | cut -d':' -f 2 )
if [ $status == "hi" ]; then
echo "success"
fi
script2.sh
#!/bin/bash
echo "blah"
status="hi"
echo "IDENTIFIER: $status"
The grep "^IDENTIFIER: " command will filter the strings from the called script, and the cut -d':' -f 2 will split the "IDENTIFIER: hi" string and get the second field, separated by the ':' character.
You might capture the output of script2 into a bash array and access the element in the array you are interested in. Contents of script2:
#!/bin/bash
echo "blah"
status="hi"
echo $status
Contents of script1:
#!/bin/bash
output_arr=( $(./script2) )
if [[ "${output_arr[1]}" == "hi" ]]; then
echo "success"
fi
Output:
$ ./script1
success
Script1:-
#!/bin/sh
cat > ed1 <<EOF
1p
q
EOF
next () {
[[ -z $(ed -s status < ed1 | grep "hi") ]] && main
[[ -n $(ed -s status < ed1 | grep "hi") ]] && end
}
main () {
sleep 1
next
}
end () {
echo $(ed -s status < ed1)
exit 0
}
Script2:-
#!/bin/sh
echo "blah"
echo "hi" >> status
script2.shbe written to standard error instead of standard output? Would it be possible to use the exit status ofscript2.shinstead of reading its standard output at all?./script2 | grep -Fq 'hi' && echo success,grephas more options/flag you might want to check it out.