Redirection in PHP exec call creates empty file

Question

It's quite simple, and I'm out of ideas. I'm sure there is a quick workaround.

exec('echo 123 &> /var/log/123.log');

I'm sure it's not about the permissions, because the file 123.log is created, but it's just- empty. I've also tried shell_exec, but it doesn't create the file at all. Also tried all variants of redirection, i.e. 1> 2> >.

Using PHP to capture the output is not the option, as the output in production is huge, and I don't want to run into memory issues.

Any ideas appreciated.

Btw, I'm using Ubuntu 12.04 LAMP.

Answer 1

Debian and Debian based Linux distributions like Ubuntu are using dash and not bash as /bin/sh by now.

&> is a bash extension, the dash does not know about.

The correct posix-compatible way to write cmd &> file is cmd > file 2>&1

cmd > file 2>&1 works in all posix-compatible shells: dash, bash, ksh, zsh, ash ...

So you need to change your code to:

exec('echo 123 > /var/log/123.log 2>&1');