One-liner to turn jar with Main-Class into executable shell script

gistfile1.txt

# turn a jar with a Main-Class into a stand alone executable

(echo '#!/usr/bin/env java -jar'; cat blahblah.jar) > blah

# turn a jar with a particular main clas into a stand alone executable

(echo '#!/usr/bin/env java -jar package.MainClass'; cat blahblah.jar) > blah

I'm pretty sure that the "$@" doesn't work for quoted strings on the command line. I ran into issues and had to come up with that insanity to get past them. Do you think it does?

The insanity came as you were using "eval" -- that causes the shell to expand and interpret the arguments provided. My modified snippet uses "exec": more efficient (since it causes the running shell to replace itself), and it doesn't do any interpretation of the arguments.

Ah, thanks for the insight!

This unfortunately doesn't work in Linux though it works great on my Mac. Linux interprets everything after the interpreter in the shebang as one big argument. So, env ends up getting "java -jar" as the exe.

While not as portable, this slight modification works. Does require java to be in /usr/bin though. :-P

(echo `#!/usr/bin/java -jar'; car blahblah.jar) > blah

@stuckj

Thanks for your help regarding Linux..
Beware of typo.. the command should look like

(echo '#!/usr/bin/java -jar'; cat blahblah.jar) > blah

Thanks.

Doesn't seem to work any more 😞 Which is strange as jar tf file shows the jar contents.

This worked for me, both in mac os and in a linux docker image.

It's working for me too. I really should have included some detail such as the OS and JVM versions that I encountered the problem.

/me blushes