Running Unix Programs From Java

> Am I doing something wrong, or am I just a lucky

> stiff - I've never had to rely on Runtime.exec?

You're lucky.

I had to use it once, to invoke ghostview or ghostscript to print a PDF doc. Ffuuggly business, that.

Runtime.exec asks Chuck Norris what it should do.

jverda at 2007-7-12 21:38:04 >

*, >, | &, etc. are interpreted by the shell.The command you're executing never sees them. When you rt.exec some command, you're bypassing the interpretation of those characters.

When you're in a terminal window, and you type ls -l *

that string of characters goes to the shell first, which turns * into aaa bbb ccc or whatever is in that directory, and then the shell invokes ls -l aaa bbb ccc.

The details differ by shell and *nix install, but roughly...

rt.exec("/bin/bash -c 'ls -l *'");

or

rt.exec(new String[] {"/bin/bash", "-c", "ls -l *"});

See the man page for your shell, but here, -c tells bash "take everything that follows as a command and its args to execute."

Also, you'll want to read this:

http://developer.java.sun.com/developer/Books/effectivejava/Chapter3.pdf

jverda at 2007-7-12 21:38:04 >

> Thank you, I have discovered that the hard way.

> "Find" doesn't work too well, either.

You're quite welcome.

There's no reason find shouldn't work though. This worked for me. I'm running XP and have cygwin installed

rt.exec("C:/cygwin/bin/bash -c 'find /tmp -print > /tmp/qweryui'");

jverda at 2007-7-12 21:38:04 >