What does the "< " symbol mean on -jar call?

Question

I'm facing a problem with calling java from php on a linux server with popen.

$java = '/usr/bin/java';
$cmd = "$java -jar javafiles/register.jar < $tmpFile";

What does the < before $tmpFile mean? Because apparently it is loading the content of $tmpFile from disk and inputting it directly on the console of the register.jar execution. Is that the case? Because the content of $tmpFile has special characters and these aren't being encoded in the right charset.

This would be the same with any other linux command, correct? It's not a java specific feature. — Patrickdev, Dec 06 '12 at 18:09
@Patrickdev: right, it has nothing to do with java, it works that way with any process that reads from stdin. — Nathan Hughes, Dec 06 '12 at 18:13

score 3 · Answer 1 · answered Dec 06 '12 at 18:06

3

Thats exactly what it does. Specifically, it runs the program and sends the contents of $tmpFile into the standard input (System.in) of the program being executed.

answered Dec 06 '12 at 18:06

Eric Petroelje

57,359
8
118
174

What does the "< " symbol mean on -jar call?

1 Answers1