How to execute Perl qx function with variable
How do I get Perl's 开发者_Go百科qx
function to execute with my $opt
variable?
Before (works):
my @df_output = qx (df -k /tmp);
I want to use either -k
, -g
, or -H
:
my @df_output = qx (df -$opt /tmp);
What you have should work, but: don't ever use qx
. It's ancient and dangerous; whatever you feed to it goes through the shell, so it's very easy to be vulnerable to shell injection or run into surprises if /bin/sh
isn't quite what you expected.
Use the multi-arg form of open()
, which bypasses the shell entirely.
open my $fh, '-|', 'df', "-$opt", '/tmp' or die "Can't open pipe: $!";
my @lines = <$fh>; # or read in a loop, which is more likely what you want
close $fh or die "Can't close pipe: $!";
try to use backslash \$opt
, it works.
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