Re: Strange system call failure in OS X

[moritz]

in reply to Strange system call failure in OS X

Right now you're assigning a single string to the array @args. Instead you can assign a list to it, and omit the quoting entirely:

@args = (qw(scutil --set ComputerName), $name);
system(@args)

Though I guess that the problem is not with quoting, but something else.

Perhaps I should insert some sort of sleep command to pause between system calls?

And what would you gain from that?

[endor-moon]

Sending a list to system is much cleaner, thank you, but the error remains. I think perhaps for now I will just delete the system call that isn't working, as when I inserted a call to get that preference, the correct value came back -- so perhaps I don't really need to set that particular value. (I read about this command on osxdaily.com.)

Regarding sleep, there was nothing to be gained. I tried a sleep 4 without any change in the error. Perhaps it is a newbie attribute to hope that inserting a sleep will make a problem go away. <grin>

[endor-moon]

I have more system calls which might be cleaner if I send them as a list. Do I break it into a separate item for each argument? Any need for quotes? Here are the other system calls. They do actually work as they are but I would like to learn how to use the system call the "right" way so to speak.

# Disable autologin
@args = ("defaults delete /Library/Preferences/com.apple.loginwindow a
+utoLoginUser");
system(@args);

# exit our test version here before doing anything irrevocable
exit 0;

# Serialize Adobe CS6 Design and Web Premium
@args = ("/Library/AdminToolBox/AdobeSerialization adobe_prtk --tool=V
+olumeSerialize --provfile=/Library/AdminToolBox/prov.xml");
system(@args);

# Bind to Active Directory
@args = ("/Library/AdminToolBox/bind.sh");
system(@args);

# This time we'll use exec since we are restarting anyway
@args = ("/sbin/shutdown -r now");
exec(@args);

[Anonymous Monk]

Do I break it into a separate item for each argument?

Yes, it is  system "/usr/bin/foobar", "arg", "arg", "--arg=arg" ...

Any need for quotes?

No. Quotes are for the shell.

See system/exec.., kinda dense/long, but essentially  system q{single "st" "ri" "ng"} could be open to shell interpolation/invoke the shell, while  system "single", "st", "ri", "ng" will avoid the shell

So list is preferable because you don't have to quote to a particular shell , just quote for perl

perlop#Quote and Quote like Operators discusses making a list with qw" st ri ng ";

While you're in a learning mood, get a free copy of Modern Perl

See also

• perlrun
• Behind the GUI lives the Shell
• Windows Command Line Interpreter|Shell|DOS Prompt|Batch Files|Scripting
• Csh Programming Considered Harmful
• How Command Line Parameters Are Parsed
• http://www.gnu.org/software/bash/manual/bashref.html#Quoting
• String::ShellQuote/Win32::ShellQuote, Re: system() implementation on Windows (again), Re^3: system() implementation on Windows (again), Everyone quotes command line arguments the wrong way
• Proc::Background
• The Windows NT Command Shell
• exec always invokes the shell? win32, System, exec different behaviour with spaces

[Anonymous Monk]

$ perl -MData::Dump -e " dd\@ARGV " "he llo" there "bu ddy"
["he llo", "there", "bu ddy"]

$ perl -MData::Dump -e " dd\@ARGV " he llo there bu ddy
["he", "llo", "there", "bu", "ddy"]

$ perl - he llo there bu ddy
use Data::Dump;
dd\@ARGV;
__END__
["he", "llo", "there", "bu", "ddy"]

$