save exec() output to file in

Question

I am executing gzip on a debian server via php using the exec() function.

gzip -1 -c file1.xxx > file1.gz  

Now I want to errors to be saved in some error.log.

1. How I can set output to file?
2. Is it better to use shell_exec()?

Answer 1

to redirect stderr to a file, use the 2> redirector (2 is the file-handle for the stderr):

gzip -1 -c file1.xxx >file1.gz  2>error.log

(see also the REDIRECTION section man bash)