| $_ |
The default parameter for a lot of functions.
|
| $. |
Holds the current record or line number of the file handle that was last
read. It is read-only and will be reset to 0 when the file handle is closed.
|
| $/ |
Holds the input record separator. The record separator is usually the
newline character. However, if $/ is set to an empty string, two or more
newlines in the input file will be treated as one.
|
| $, |
The output separator for the print() function. Nor-mally, this variable is
an empty string. However, setting $, to a newline might be useful if you need
to print each element in the parameter list on a separate line.
|
| $ |
Added as an invisible last element to the parameters passed to the print()
function. Normally, an empty string, but if you want to add a newline or some
other suffix to everything that is printed, you can assign the suffix to $.
|
| $# |
The default format for printed numbers. Normally, it's set to %.20g, but
you can use the format specifiers covered in the section "Example: Printing
Revisited" in Chapter 9to specify your own default format.
|
| $% |
Holds the current page number for the default file handle. If you use select
() to change the default file handle, $% will change to reflect the page
number of the newly selected file handle.
|
| $= |
Holds the current page length for the default file handle. Changing the
default file handle will change $= to reflect the page length of the new file
handle.
|
| $- |
Holds the number of lines left to print for the default file handle.
Changing the default file handle will change $- to reflect the number of lines
left to print for the new file handle.
|
| $~ |
Holds the name of the default line format for the default file handle.
Normally, it is equal to the file handle's name.
|
| $^ |
Holds the name of the default heading format for the default file handle.
Normally, it is equal to the file handle's name with _TOP appended to it.
|
| $| |
If nonzero, will flush the output buffer after every write() or print()
function. Normally, it is set to 0.
|
| $$ |
This UNIX-based variable holds the process number of the process running
the Perl interpreter.
|
| $? |
Holds the status of the last pipe close, back-quote string, or system()
function.
|
| $& |
Holds the string that was matched by the last successful pattern match.
|
| $` |
Holds the string that preceded whatever was matched by the last successful
pattern match.
|
| $' |
Holds the string that followed whatever was matched by the last successful
pattern match.
|
| $+ |
Holds the string matched by the last bracket in the last successful pattern
match. For example, the statement /Fieldname: (.*)|Fldname: (.*)/ && ($fName =
$+); will find the name of a field even if you don't know which of the two
possible spellings will be used.
|
| $* |
Changes the interpretation of the ^ and $ pattern anchors. Setting $* to 1
is the same as using the /m option with the regular expression matching and
substitution operators. Normally, $* is equal to 0.
|
| $0 |
Holds the name of the file containing the Perl script being executed.
|
| $ |
This group of variables ($1, $2, $3, and so on) holds the regular
expression pattern memory. Each set of parentheses in a pattern stores the
string that match the components surrounded by the parentheses into one of the $ variables.
|
| $[ |
Holds the base array index. Normally, it's set to 0. Most Perl authors
recommend against changing it without a very good reason.
|
| $] |
Holds a string that identifies which version of Perl you are using. When
used in a numeric context, it will be equal to the version number plus the
patch level divided by 1000.
|
| $" |
This is the separator used between list elements when an array variable is
interpolated into a double-quoted string. Normally, its value is a space
character.
|
| $; |
Holds the subscript separator for multidimensional array emulation. Its use
is beyond the scope of this book.
|
| $! |
When used in a numeric context, holds the current value of errno. If used
in a string context, will hold the error string associated with errno.
|
| $@ |
Holds the syntax error message, if any, from the last eval() function call.
|
| $< |
This UNIX-based variable holds the read uid of the current process.
|
| $> |
This UNIX-based variable holds the effective uid of the current process.
|
| $) |
This UNIX-based variable holds the read gid of the current process. If the
process belongs to multiple groups, then $) will hold a string consisting of
the group names separated by spaces.
|
| $: |
Holds a string that consists of the characters that can be used to end a
word when word-wrapping is performed by the ^ report formatting character.
Normally, the string consists of the space, newline, and dash characters.
|
| $^D |
Holds the current value of the debugging flags. For more information.
|
| $^F |
Holds the value of the maximum system file description. Normally, it's set
to 2. The use of this variable is beyond the scope of this book.
|
| $^I |
Holds the file extension used to create a backup file for the in-place
editing specified by the -i command line option. For example, it could be
equal to ".bak."
|
| $^L |
Holds the string used to eject a page for report printing.
|
| $^P |
This variable is an internal flag that the debugger clears so it will not
debug itself.
|
| $^T |
Holds the time, in seconds, at which the script begins running.
|
| $^W |
Holds the current value of the -w command line option.
|
| $^X |
Holds the full pathname of the Perl interpreter being used to run the
current script.
|
| $ARGV |
Holds the name of the current file being read when using the diamond
operator (<>).
|
| @ARGV |
This array variable holds a list of the command line arguments. You can use
$#ARGV to determine the number of arguments minus one.
|
| @F |
This array variable holds the list returned from autosplit mode. Autosplit
mode is associated with the -a command line option.
|
| @INC |
This array variable holds a list of directories where Perl can look for
scripts to execute. The list is mainly used by the require statement.
|
| %INC |
This hash variable has entries for each filename included by do or require
statements. The key of the hash entries are the filenames, and the values are
the paths where the files were found.
|
| %ENV |
This hash variable contains entries for your current environment variables.
Changing or adding an entry affects only the current process or a child
process, never the parent process. See the section "Example: Using the %ENV
Variable" later in this chapter.
|
| %SIG |
This hash variable contains entries for signal handlers. For more
information about signal handlers
_
This file handle (the underscore) can be used when testing files. If used,
the information about the last file tested will be used to evaluate the new
test.
|
| DATA |
This file handle refers to any data following __END__.
|
| STDERR |
This file handle is used to send output to the standard error file.
Normally, this is connected to the display, but it can be redirected if
needed.
|
| STDIN |
This file handle is used to read input from the standard input file.
Normally, this is connected to the keyboard, but it can be changed.
|
| STDOUT |
This file handle is used to send output to the standard output file.
Normally, this is the display, but it can be changed. |
