How to use awk in a Perl program

Question: I now want to add awk ' {print $} ' from_file > To_file to the Perl program, but after adding sytem and ', I can't do it.

Answer: There are a number of commands that can be executed at the command line, but they cannot be executed directly in Perl, and special characters need to be escaped. $ before all plus \ Try, or the $ $ will be considered a variable in Perl.
It is better to write directly in Perl than to write, you write awk ' {print $} ' from_file > to_file into a shell script, execute it successfully, and then put the shell script into Perl's system.

Perl writes as follows:
System ("awk ' {print $} ' from_file > To_file") runs ok~