System commands and curly braces

erwos has asked for the wisdom of the Perl Monks concerning the following question:

I'm trying to run a command via system() that has curly braces in its argument. It looks something like this:

`some_command a={1,2},{3,4}`;

What the system apparently tries to execute is:

some_command a=1,2,3,4

That is to say, no curly braces get included. I don't have the option to use anything but curly braces, and I cannot use whitespace to separate out the curly braces at all. Using a literal string ('') in a proper system() command doesn't fix it, either.

Does anyone have a solution or workaround? I've been wrestling with this one for a bit, but haven't even found anything on Google.

Thanks!

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Re: System commands and curly braces by ikegami (Patriarch) on Aug 10, 2010 at 18:49 UTC
You're invoking the shell, and those characters have special meaning to your shell. `$ echo some_command a={1,2},{3,4} some_command a=1,3 a=1,4 a=2,3 a=2,4` [download] You need to pass a shell literal that produces the desired arg, not the arg itself. `$ echo some_command 'a={1,2},{3,4}' some_command a={1,2},{3,4}` [download] sub text_to_sh_literal { my ($s) = @_; s/'/'\\''/g; return "'$s'"; } my $arg_lit = text_to_sh_literal($arg); `some_command $arg_lit` [download] You could also avoid the shell. `open(my $fh, '-\|', 'some_command', $arg); <$fh>` [download]	[reply] [d/l] [select]
Re: System commands and curly braces by toolic (Bishop) on Aug 10, 2010 at 17:45 UTC
Try to escape the curly braces: `some_command a=\{1,2\},\{3,4\}`; [download] Here is a complete example (on linux), using system instead of backticks to show the output: `$ cat foo.pl #!/usr/bin/env perl use strict; use warnings; system './some_command a=\{1,2\},\{3,4\}'; $ $ cat some_command #!/usr/bin/env perl use strict; use warnings; use Data::Dumper; print Dumper(\@ARGV); $ $ ./foo.pl $VAR1 = [ 'a={1,2},{3,4}' ]; $` [download]	[reply] [d/l] [select]