Redirect java -version to file or variable

问题

Maybe it is a silly question, but I'm trying to redirect the exit of "java -version" command to a file or variable but it doesn't work.

Server = Linux CentOS 6

My code in shell script

java -version >> test.txt

Also I'm trying to assign it to a variable:

JAVA_CHECK=`java -version`

Even running those command from command-line it still not working.

when I say it doesnt work, I mean that the exit of the command is being showed in my screen instead to redirect it to a file or wherever

...

回答1:

java -version writes to stderr (fileno 2), not stdout (fileno 1). You can redirect stderr to a file:

java -version 2> test.txt
# cat test.txt 
# java version "1.7.0_25"
# OpenJDK Runtime Environment
# [...]

Or you can redirect stderr to stdout:

java_check=$(java -version 2>&1)
# echo "$java_check"
# java version "1.7.0_25" OpenJDK Runtime Environment [...]

来源：https://stackoverflow.com/questions/21453774/redirect-java-version-to-file-or-variable