Bash - variable in the process

I wrote a script:

Old script:

var="$(sleep 5 && echo "Linux is...")" &
sleep 5
echo $var

New script:

var="$(cat file | grep Succeeded && kilall cat)" & killer1=$!
(sleep 60; kill $killer1) & killer2=$!
fg 1
kill $killer2
e开发者_如何学Gocho $var

Cat file works all the time. Should return "... \n Succeeded \n ...". Echo empty always returns. Is there a solution? I want to necessarily result in a variable.

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When you terminate a command by &, the shell executes the command in a subshell. var is set in the subshell, not the original process.

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If you run it on the background using &, it is in separate process, so you no more share variables. You need to use IPC (interprocess comunication) to assure this. Easiest IPC to use is a pipe:

{ sleep 2 && echo 'Linux is ...' ; } | 
{ 
echo 'doing something here in the meantime...'
sleep 1
read var 
echo $var
}

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Remove the & from the assignment of var (line 1 in your script).