I am running Apache2 on a CentOS 5.8 x64 server, with many virtual hosts set up. Each virtual host has its own error_log and access_log, however in the, "main" error_log (/var/log/httpd/error_log) I have, for the last week or so, begun to see the following line:
sh: zip: command not found
There is no other information attached - no date, no time, no IP, no referrer, nothing - just the above. Typically I will see this line repeated 10, 20 or more times, though sometimes it only gets repeated once or twice before the next event gets logged.
Google search reveals this error is seen mainly in the context of compiling programs when the zip binary is not present or the path is not specified correctly...I would hope my Apache and web sites are not doing any type of compiling! Why am I getting this error? What Apache site or directive (?) is trying to zip something - and why is it appearing in the main error_log?
Any idea what this error line is telling me (other than the obvious, that it can't find the proper path to the zip binary)?