[Bash]检查java版本信息

#!/bin/bash
#set -x
if type -p java; then
echo "found java executable in PATH"
_java=java
elif [[ -n "$JAVA_HOME" ]] && [[ -x "$JAVA_HOME/bin/java" ]]; then
echo "found java executable in JAVA_HOME"
_java="$JAVA_HOME/bin/java"
else
echo "No Java"
fi

if [[ "$_java" ]]; then
# version=$("$_java" -version 2>&1 | awk -F '"' '/version/ {print $2}')
#it will give you 16 for java like 1.6.0_13 and 15 for version like 1.5.0_17.
version=$(java -version 2>&1 | sed 's/java version "(.*).(.*)..*"/12/; 1q')
echo version "$version"
[ "$version" -ge 15 ] && echo "ok, java is 1.5 or newer" || echo "it's too old..."
fi