Bash Compound/Nested Conditional Operator issue

Question

I have my Bash code like this:

copiedFlag=false
..
if [...]
cp originalFile newFile && copiedFlag=true
fi
..
if[....]
copiedFlag || ( cp originalFile newFile && copiedFlag=true )
fi
..

if [ copiedFlag == true ]; then
cp newFile originalFile
fi
..

The compound condition copiedFlag || ( cp originalFile newFile && copiedFlag=true ) somehow doesn't work.

But if I do this, it works: copiedFlag || cp originalFile newFile && copiedFlag=true

This is an important step in my logic, hence I want to ensure that my assignment is absolutely correct by enclosing it in braces. Why does this not work? What am I doing wrong?

I guess you missed a $: $copiedFlag || ( cp originalFile newFile && copiedFlag=true ) — Leon
– Leon, Commented Aug 23, 2017 at 11:06
You must dereference/expand copiedFlag everywhere outside assignments to it, thus also in if [ $copiedFlag == true ]; then ... — Leon
– Leon, Commented Aug 23, 2017 at 11:16

Leon · Accepted Answer · 2017-08-23 11:12:05Z

1

The compound condition copiedFlag || ( cp originalFile newFile && copiedFlag=true ) somehow doesn't work.

It doesn't work because you are forking a new subshell and changes made to copiedFlag are not visible in current shell.

You don't really need to spawn a subshell here, just use brace expression { ...; } as:

"$copiedFlag" || { cp originalFile newFile && copiedFlag=true; }

edited Aug 23, 2017 at 11:12

Leon

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answered Aug 23, 2017 at 11:07

anubhava

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2 Comments

Leon Over a year ago

The test must start with a $: $copiedFlag || { cp originalFile newFile && copiedFlag=true; }

user1880957 Over a year ago

Great Anubhava. I had put the $ alright, but I think the curly brace is the winner. ! will try it out and update shortly.

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