Perl reference

Reference for various things in Perl. See also Perl built-in functions.

Escape Sequences

\a	bell (ctrl-G, 007 decimal)
\b	backspace (ctrl-H, 008 decimal)
\cn	ctrl-n
\e	ESC (027 decimal, 033 octal)
\f	FF
\l	converts next letter to lowercase
\n	newline - system-dependent (CRLF on DOS/Win)
\r	CR (013 decimal)
\t	TAB (ctrl-I, 009 decimal)
\u	converts next letter to uppercase
\L	converts all characters to lowercase, from here to next \E
\U	converts all characters to uppercase, from here to next \E
\E	ends case conversion started by \L or \U
\'	prints a literal single-quote
\"	prints a literal double-quote
\$	prints a literal dollar sign
\\	prints a literal backslash (not doubled)
\0nnn	prints the ASCII character numbered nnn in octal
\xnn	prints the ASCII character numbered nn in hexadecimal

File Test Operators

All operators are used like this:

-x $filename

-r	Is the file readable?
-w	Is the file writable?
-x	Is the file executable?
-e	Does the file exist?
-z	Is the file empty? (i.e. zero bytes)
-s	File length in bytes
-f	Is the file an ordinary file?
-d	Is the file a directory?
-l	Is the file a symbolic link? (UNIX/Linux only)
-p	Is file a named pipe?
-S	Is the file a socket?
-T	Is the file a text file?
-B	Is the file a binary file? (!-T)
-M	Number of days since file was last modified
-A	Number of days since file was last accessed