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Perl Language Reference Manual
by Larry Wall and others
Paperback (6"x9"), 724 pages
ISBN 9781906966027
RRP £29.95 ($39.95)

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29.5 E

eclectic
Derived from many sources. Some would say too many.
element
A basic building block. When you're talking about an array, it's one of the items that make up the array.
embedding
When something is contained in something else, particularly when that might be considered surprising: "I've embedded a complete Perl interpreter in my editor!"
empty subclass test
The notion that an empty derived class should behave exactly like its base class.
en passant
When you change a value as it is being copied. [From French, "in passing", as in the exotic pawn-capturing maneuver in chess.]
encapsulation
The veil of abstraction separating the interface from the implementation (whether enforced or not), which mandates that all access to an object's state be through methods alone.
endian
See little-endian and big-endian.
environment
The collective set of environment variables your process inherits from its parent. Accessed via %ENV.
environment variable
A mechanism by which some high-level agent such as a user can pass its preferences down to its future offspring (child processes, grandchild processes, great-grandchild processes, and so on). Each environment variable is a key/value pair, like one entry in a hash.
EOF
End of File. Sometimes used metaphorically as the terminating string of a here document.
errno
The error number returned by a syscall when it fails. Perl refers to the error by the name $! (or $OS_ERROR if you use the English module).
error
See exception or fatal error.
escape sequence
See metasymbol.
exception
A fancy term for an error. See fatal error.
exception handling
The way a program responds to an error. The exception handling mechanism in Perl is the eval ( ) operator.
exec
To throw away the current process's program and replace it with another without exiting the process or relinquishing any resources held (apart from the old memory image).
executable file
A file that is specially marked to tell the operating system that it's okay to run this file as a program. Usually shortened to "executable".
execute
To run a program or subroutine. (Has nothing to do with the kill ( ) built-in, unless you're trying to run a signal handler.)
execute bit
The special mark that tells the operating system it can run this program. There are actually three execute bits under Unix, and which bit gets used depends on whether you own the file singularly, collectively, or not at all.
exit status
See status.
export
To make symbols from a module available for import by other modules.
expression
Anything you can legally say in a spot where a value is required. Typically composed of literals, variables, operators, functions, and subroutine calls, not necessarily in that order.
extension
A Perl module that also pulls in compiled C or C++ code. More generally, any experimental option that can be compiled into Perl, such as multithreading.
ISBN 9781906966027Perl Language Reference ManualSee the print edition