I am having trouble figuring out why am I getting the error defined in the title.

This is the line of code I'm inputting into the command line:

perl -pi -e 's/(\/(?:(?:https?|ftp|file):\/\/|www\.|ftp\.)' myfilepath

Basically, what I'm trying to do is go through a body of text, find all the URLS and append something to the end of the domain. For example: https://thisisalink.com/navigate/page <-- I want to ignore the ]

I keep getting this error when I run that code though:

Unmatched [ in regex; marked by <-- HERE in *)|[ <-- HERE A-Z0-9 &@#%=~_|5.030003)/gxi)/ at -e line 1, <> line 1.

How to fix this issue?

CodePudding user response：

$] is a special variable that contains the current version of the Perl interpreter used. Hence, [A-Z0 9 &@#%=~_|$] is interpolated as [A-Z0 9 &@#%=~_|5.032001 (on my Perl 5.32.1), and the opening [ is thus unmatched. To fix this, escape the $ using \$:

[A-Z0 9 &@#%=~_|\$]

Similarly, earlier in the regex, you are using [...$?...], except that $? is also a special variable containing The status returned by the last pipe close, backtick (``) command, successful call to wait() or waitpid(), or from the system() operator. This does not cause any error since it should be an integer, but it will no match either $ or ? as you'd like. Once again, escape the $ using \$?.

In general, when you want to match a literal $, you should probably escape it.