[SOLVED] Calling a system command in Perl

[cheesecake42]

I'm trying to call a system command in perl and am having an issue with it.

Here's an example of a command i'd like to call:

sed -i '4 c\192.168.1.4  www.something.com' hosts

this is the section in my perl script where I create the variable and call it:

$doit = `sed -i '$line c\$ip    $host hosts'`
system($doit);

The $line, $ip, and $host variables are working fine becasue I can replace that section with "prints" and they come out fine. I imagine the problem is where I am creating the $doit variable.

Thanks!

[scathefire]

this may sound silly, but have you tried

system("$doit");

[cheesecake42]

That gave me the same extremely vague error:

syntax error at ./sedtest line 73, near "system"
Execution of ./sedtest aborted due to compilation errors.

Line 73 is the following:

system($doit);

[scathefire]

well in what you posted

$doit = `sed -i '$line c\$ip    $host hosts'`

there is a semicolon missing at the end

i wouldn't use the ticks either. i'd make it more like:

system("sed -i '$line c\$ip     $host hosts'");

does that work any better?

[cheesecake42]

It's getting closer. I got rid of the command variable and changed the system() part to have the full command like you listed it. It errored so I cahnged the system() part to just print and it appears that the "\" before "c" is disappearing in the print.

[scathefire]

yeah that '\' has special meaning as an escape character in the shell.

perhaps parts of it need to be fed in as a scalar variable.

$sedline = "'$line c\$ip     $host hosts'";
system("sed -i $sedline");

you can also try exec() instead of system().

basically we just have to trick it into not seeing that '\' as an escape character. you may also try using '\\'. Sometimes I run into the same problem when processing '?' in URLs that are passed to system().

[cheesecake42]

dur, i didnt even think to use the second backslash. That did it (plus moving the single quotation mark from the end of hosts back to $host).

[cheesecake42]

So Just in case this extremely obscure question is needing to be answered by anybody else, here's the final solution:

system("sed -i '$line c\\$ip    $host' hosts");