Don't understand the practical difference between command aliases and environmental variables
Hey,
I'm recently learning Unix from the video course by Kevin Scoglund. I'm stuck at the moment where he goes into Environmenat variables. I have some issues with understanding what's the essential difference between EV and command aliases: for instance, by writing the command
Code:
alias ll='ls -lahG'
into .bashrc file we ensure that typing every time the shortcut ll we get the whole bunch of modifications to the original command executed whenever we type it.
ALong with that we have so called "environmental variables" (f.e., export LESS='-N') we could equal to any value ("variable") that theoretically when saved to .bashrc should trigger that command exactly as we predefined it.
According to Mr. Scoglund it should work once we launch another Terminal session by opening a new window ir by executing
Code:
source .bashrc
. However, when trying the former it fails to do so (no command found), so I have to rely on the latter which is pain in the ass typing it in every time. It should be mentioned he worked with Snow Leopard while I'm on Lion, so definitely some changes occurred here.
So:
(1) I can't execute .bashrc file commands unless I execute
Code:
source .bashrc
Is there less labourous method of doing that without
Code:
source .bashrc
in Lion?
(2) what's the point of EV since one could assign an alias to a command and the result is pretty much the same?
If I sound dumb forgive me since I was forced to skip that entire chapter about profile, login and resource files due to corrupted video file containing that part so I might have missed some points completely hence is my confusion.
Last edited by scrutinizerix; 01-10-2016 at 07:29 AM..
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LEARN ABOUT MOJAVE
locale::codes::langext5.18
Locale::Codes::LangExt(3pm) Perl Programmers Reference Guide Locale::Codes::LangExt(3pm)NAME
Locale::Codes::LangExt - standard codes for language extension identification
SYNOPSIS
use Locale::Codes::LangExt;
$lext = code2langext('acm'); # $lext gets 'Mesopotamian Arabic'
$code = langext2code('Mesopotamian Arabic'); # $code gets 'acm'
@codes = all_langext_codes();
@names = all_langext_names();
DESCRIPTION
The "Locale::Codes::LangExt" module provides access to standard codes used for identifying language extensions, such as those as defined in
the IANA language registry.
Most of the routines take an optional additional argument which specifies the code set to use. If not specified, the default IANA language
registry codes will be used.
SUPPORTED CODE SETS
There are several different code sets you can use for identifying language extensions. A code set may be specified using either a name, or
a constant that is automatically exported by this module.
For example, the two are equivalent:
$lext = code2langext('acm','alpha');
$lext = code2langext('acm',LOCALE_LANGEXT_ALPHA);
The codesets currently supported are:
alpha
This is the set of three-letter (lowercase) codes from the IANA language registry, such as 'acm' for Mesopotamian Arabic.
This is the default code set.
ROUTINES
code2langext ( CODE [,CODESET] )
langext2code ( NAME [,CODESET] )
langext_code2code ( CODE ,CODESET ,CODESET2 )
all_langext_codes ( [CODESET] )
all_langext_names ( [CODESET] )
Locale::Codes::LangExt::rename_langext ( CODE ,NEW_NAME [,CODESET] )
Locale::Codes::LangExt::add_langext ( CODE ,NAME [,CODESET] )
Locale::Codes::LangExt::delete_langext ( CODE [,CODESET] )
Locale::Codes::LangExt::add_langext_alias ( NAME ,NEW_NAME )
Locale::Codes::LangExt::delete_langext_alias ( NAME )
Locale::Codes::LangExt::rename_langext_code ( CODE ,NEW_CODE [,CODESET] )
Locale::Codes::LangExt::add_langext_code_alias ( CODE ,NEW_CODE [,CODESET] )
Locale::Codes::LangExt::delete_langext_code_alias ( CODE [,CODESET] )
These routines are all documented in the Locale::Codes::API man page.
SEE ALSO
Locale::Codes
The Locale-Codes distribution.
Locale::Codes::API
The list of functions supported by this module.
http://www.iana.org/assignments/language-subtag-registry
The IANA language subtag registry.
AUTHOR
See Locale::Codes for full author history.
Currently maintained by Sullivan Beck (sbeck@cpan.org).
COPYRIGHT
Copyright (c) 2011-2013 Sullivan Beck
This module is free software; you can redistribute it and/or modify it under the same terms as Perl itself.
perl v5.18.2 2013-11-04 Locale::Codes::LangExt(3pm)
01-09-2016
so I might have missed some points completely hence is my confusion.