如何在远程主机解析java -version版本号并赋值给变量

Got it, let's break this down into a clean, single command that does exactly what you need: run java -version on a remote Linux host, parse the version number, and save it to a local variable.

The One-Liner #

REMOTE_JAVA_VERSION=$(ssh your-username@remote-host 'java -version 2>&1 | grep -E "version" | sed -E "s/.*version \"([0-9]+\.[0-9]+\.[0-9]+).*/\1/"')

Let's Break Down Each Part #

• ssh your-username@remote-host '...': Establishes an SSH connection to your remote host and runs the command inside the single quotes on that machine.
• java -version 2>&1: By default, java -version outputs to stderr (standard error) instead of stdout. The 2>&1 redirects stderr to stdout, so our next commands can capture the output properly.
• grep -E "version": Filters the output to only the line containing the version string—this works for both OpenJDK and Oracle JDK, which have slightly different but compatible output formats.
• sed -E "s/.*version \"([0-9]+\.[0-9]+\.[0-9]+).*/\1/": Uses a regular expression to extract the core version number (e.g., pulls 11.0.18 from openjdk version "11.0.18" 2023-01-17).

Want the Full Version String? #

If you need the complete version string including update numbers or distribution-specific suffixes (like 1.8.0_361 or 11.0.18+10-post-Ubuntu-0ubuntu122.04), adjust the sed part to capture everything inside the quotes:

REMOTE_JAVA_VERSION=$(ssh your-username@remote-host 'java -version 2>&1 | grep -E "version" | sed -E "s/.*version \"([^\"]+)\".*/\1/"')

Important Notes #

• SSH Access: Make sure your local machine can connect to the remote host via SSH. For non-interactive use (so the command runs without prompting for a password), set up SSH key-based authentication.
• Java Path: If Java isn't in the remote user's default PATH, specify the full path to the Java executable (e.g., /usr/lib/jvm/java-11-openjdk-amd64/bin/java -version).
• Output Variations: Some older Java versions might have slightly different output formats, but the above commands should work for most modern OpenJDK and Oracle JDK releases.

内容的提问来源于stack exchange，提问作者jdoe08