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
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
. 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
Is there less labourous method of doing that without
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..
i have been trying to understand this chapter titled "Searching for Files and Text" for a few weeks now.
unfortunately, this chapter is one of those things, that no matter how hard you try and how long you try for, you are incapable of understanding (at least in my case)
this entire chapter,... (2 Replies)
Hi all !
Yesterday I defined an environmental variable PATH, but today when I restarted machine, I could not see that it was stored any place.
Is there any file where I could save the settings ?
I have quite a few env.variables defined, so I need a smarter way to define.
regards
D (5 Replies)
Hi all,
I have a script with those two lines :
test -f $PWD/mysetup.txt
. $PWD/mysetup.txt
I understand the first one, but could anyone explain me the role of the second one? All the thing I find is the usage :
Thx in advance (3 Replies)
Hi,
I'm using an array that contains compiler FLAGS
that need to be executed either before ./configure
or after the main 'make' command.
example of array containing compiler flags.
-------------------------------------------------
FLAGS="CFLAGS=\"-arch x86_64 -g -Os -pipe... (7 Replies)
I am writing a few korn scripts to be used by all our operators on several 4.1/4.2 AIX servers.
I want to create environmental variables that once set, can be read/modified by my scripts (ex: specific folders, file names, conventions, general values, ...). I thought this would be better then... (4 Replies)
Use and complete the template provided. The entire template must be completed. If you don't, your post may be deleted!
1. The problem statement, all variables and given/known data:
1)find all lines in file ,myf that contain all the words cat dog and mouse in any order and start with the letter... (1 Reply)
I have a text file called file1 which contains the text: "ls -l"
When I enter this command:
bash < file1 > file1
file1 gets erased. However if I enter this command:
bash < file1 > newfile
the output from "ls -l" is stored in newfile. My question is why doesn't file1's text ("ls -l") get... (3 Replies)
Hi there,
I have a very general question. I'm rather new to (bash) shell scripting and I don't understand how conditions work... I've read numerous tutorials but I don't get it. I really don't. Sometime what I do works, sometime it doesn't and that's frustating. So what's the actual difference... (0 Replies)