Cannot run command from CGI

[Kalin Evtimov]

HI!
In a cgi-script I am trying to run

system ("/bin/top -d1 > /tmp/top.out");

this doesn't write anything to the file. Why?

Greetings!
Kalin

[Warren_9]

hi,

try "top -d 1 -f /tmp/top.out"

GOOD LUCK!!

[Kalin Evtimov]

It doesn't seem to ba e syntax problem, because from the command line they both work.

[Peter Godron]

Kalin,
To eliminate any problem with file creation:
system("echo test > /tmp/top.out");
if that works at least you have narrowed the problem to the top command.
Please Update

[Kalin Evtimov]

system("echo test > /tmp/top.out");

That worked!

What could be wrong with the top command, this is a bit difficult for me..:(

[Steve Lewis · Accepted solution]

No. You must use -f if you want to send the output of top to a file, or else it will not be readable.

You have not writted how your CGI system command is executed. Is it from perl? from awk? from ruby? from python? from php?

the top command is definitely
"/bin/top -d 1 -f /tmp/top.out"

but if another user has already created that file, length zero, then your www user will not be able to overwrite it.

Check the output file permissions.

[Kalin Evtimov]

I am using the web-server from the Webmin-tool for UNIX Administration.
Thank you for the advice!

[Peter Godron]

Kalin,
so the re-direct works.
No try and capture any error messages:
system("/usr/bin/top -d1 > /tmp/top.out 2>&1");

[Kalin Evtimov]

Thank you for your idea Peter!
Steve's suggestion worked for me, I had to delete the top.out file once, so that it is could be created again from the webserver-user.

Greetings!
Kalin