将变量从perl脚本发送到命令行

Question

I have a perl script that always returns yesterday's date and the date is stored on a variable called $yesterday

Now, I am running that perl script using cmd prompt. After it figures out what yesterday's date was I would like to pass $yesterday somehow into the cmd line so that it can open up a "$yesterday.txt" file. The txt files are already there and match the date format in the filename.

Answer 1

Are you asking how to open a file?

my $file = "$yesterday.txt";
open my $fh, "<", $file or die "Cannot open $file for reading: $!";

See the documentation for more information on the open command.

Answer 2

You can simply include the $variable in the string of the command or use string concatenation to put the static and variable parts together:

system("echo yesterday >$yesterday.txt");

or

system("echo yesterday >" . $yesterday . ".txt");

The above calls a commandline program or command from perl and the command includes the value of your $yesterday variable.