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How can I store the result of grep -c as an integer in a shell variable?

This:

check=sudo virsh list |egrep -c '\b[0-9]{2}\b'

only gives me the number of matches and prints it on screen whereas the value of check is NULL.

If I execute :

check=`sudo virsh list |egrep -c '\b[0-9]{2}\b'`

I get an error that says

./test: 1 :Not found

where 1 is the number of matches.

share|improve this question
    
I fixed your markup, since the forum code borked your code examples as they were. Note the comment on David's answer: you have probably accidentally entered a space character somewhere around the = sign in the second example. A minimal example is to test: check=`echo 1`, which works, and then check= `echo 1` which returns bash: 1: command not found (or technically runs a command named "1" if it exists in the path). – Daniel Andersson Aug 6 '13 at 15:21

Like this:

check=$(sudo virsh list | egrep -c '\b[0-9]{2}\b')

$(command) behaves like a variable where the value is the output of command.

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1  
Note that it is very important not to have spaces around the = sign -- from the error description, it sounds like that may be part of the original problem. – Gordon Davisson Aug 6 '13 at 14:47

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