Perl parameter symbol (Memo)

Perl built-in variables:-01-04 are Perl built-in variables that you know. If you have any missing variables, post them to add them:

$-Number of printable lines on the current page, part of the perl format system
$! Returns the error code or string based on the context content.
$ "List Separator
$ # Default digital output format when printing numbers
$ Perl interpreter process ID
$ % Current page number of the current output channel
$ & String matching the previous format
$ (Group ID of the current process
$) Valid group ID of the current process
$ * Setting 1 indicates processing the multiline format. It is replaced by the/s and/M modifiers.
$, Delimiter of the current output field
$. Current row number of the last Read File
$/Delimiter of the current input record. The default value is a new line.
$: Character setting. Subsequent strings are separated to fill continuous fields.
$; Delimiter used to simulate multi-dimensional arrays.
$? Returns the status of the last external command.
$ @ Error message returned by the perl interpreter from the eval statement
$ [Index number of the first element in the array
$/Delimiter of the current output record
$] Sub-version number of the perl interpreter
$ ^ Name of the top page output format of the current channel
$ ^ A variables used to save formatted data before printing
$ ^ Value of the d test mark
$ ^ E Operating System Extension error message in non-Unix environment
$ ^ F maximum file bundle operator Value
$ ^ H check status of the syntax activated by the compiler
$ ^ I built-in control editor Value
$ ^ L form feed sent to the output channel
$ ^ M backup memory pool size
$ ^ O operating system name
$ ^ P specifies the internal variable of the current debugging Value
$ ^ R result of the last evaluation of the regular expression Block
$ ^ S current interpreter status
$ ^ T start from the new century, and the start time of the notebook is calculated in seconds.
$ ^ W current value of the warning Switch
$ ^ X Perl binary executable Code Name
$ _ Default input/output and format matching space
$ | Controls the buffer of the currently selected output file handle
$ ~ Name of the current report format
$ 'String before matching information in the previous format
$ 'String after matching information in the previous format
$ + The last parenthesis matching the previous regular expression search format
$ <Real id of the user currently executing the interpreter
$ <Digits> contains parentheses corresponding to the previous regular expression.
$ = Number of printable rows on the current page
$> Valid user ID of the current process
File name containing the script being executed
$ Argv current file name when reading from the default file handle
% ENV Environment Variable list
% Inc list of files contained through do or require
% Sig signal list and Processing Method
@ _ Send to Sub-Account Program Parameter List
@ Argv: List of command line parameters passed to the script
@ INC: List of directories to be searched during module Import