Store eval output in variable

Question

I'm new to Bash and trying to store eval command output in a variable. This is my code to check Java version:

javaPath="/opt/Java/i386/jre1.8.0_181/bin/Java -version"
output=eval $javaPath
echo "Java version is: $output"

Output:

java version "1.8.0_181"
Java(TM) SE Runtime Environment (build ...)
Java HotSpot(TM) 64-Bit Server ...
Java version is:

Question: how can I store command output in $output?

Inian · Accepted Answer · 2018-08-02 11:51:06Z

4

You don't need to use eval here. Don't use it unless you clearly know what you are trying to do with it. See Eval command and security issues

For your use case, though a simple function would suffice. Also I see the java -version gets printed to standard error stream stderr(2) instead of stdout(1).

javaVersion() {
    /opt/Java/i386/jre1.8.0_181/bin/Java -version 2>&1 >/dev/null
}

and put the result in a variable using command substitution, $(..) which runs your command puts the result in a variable

ouput="$(javaVersion)"
printf '%s\n' "$output"

edited Aug 2, 2018 at 11:51

answered Aug 2, 2018 at 11:36

Inian

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