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..
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)
Discussion started by: hypsis
0 Replies
LEARN ABOUT DEBIAN
irsend
IRSEND(1) User Commands IRSEND(1)NAME
irsend - basic LIRC program to send infra-red commands
SYNOPSIS
irsend [options] DIRECTIVE REMOTE CODE [CODE...]
DESCRIPTION
Asks the lircd daemon to send one or more CIR (Consumer Infra-Red) commands. This is intended for remote control of electronic devices such
as TV boxes, HiFi sets, etc.
DIRECTIVE can be:
SEND_ONCE - send CODE [CODE ...] once
SEND_START - start repeating CODE
SEND_STOP - stop repeating CODE
LIST - list configured remote items
SET_TRANSMITTERS - set transmitters NUM [NUM ...]
SIMULATE - simulate IR event
REMOTE is the name of a remote, as described in the lircd configuration file.
CODE is the name of a remote control key of REMOTE, as it appears in the lircd configuration file.
NUM is the transmitter number of the hardware device.
For the LIST DIRECTIVE, REMOTE and/or CODE can be empty:
LIST "" "" - list all configured remote names
LIST REMOTE "" - list all codes of REMOTE
LIST REMOTE CODE - list only CODE of REMOTE
The SIMULATE command only works if it has been explicitly enabled in lircd.
-h --help
display usage summary
-v --version
display version
-d --device
use given lircd socket [/var/run/lirc/lircd]
-a --address=host[:port]
connect to lircd at this address
-# --count=n
send command n times
EXAMPLES
irsend LIST DenonTuner ""
irsend SEND_ONCE DenonTuner PROG-SCAN
irsend SEND_ONCE OnkyoAmpli VOL-UP VOL-UP VOL-UP VOL-UP
irsend SEND_START OnkyoAmpli VOL-DOWN ; sleep 3
irsend SEND_STOP OnkyoAmpli VOL-DOWN
irsend SET_TRANSMITTERS 1
irsend SET_TRANSMITTERS 1 3 4
irsend SIMULATE "0000000000000476 00 OK TECHNISAT_ST3004S"
FILES
/etc/lirc/lircd.conf
Default lircd configuration file. It should contain all the remotes, their infra-red codes and the corresponding timing and wave-
form details.
DIAGNOSTICS
If lircd is not running (or /var/run/lirc/lircd lacks write permissions) irsend aborts with the following diagnostics:
"irsend: could not connect to socket"
"irsend: Connection refused" (or "Permission denied").
SEE ALSO
The documentation for lirc is maintained as html pages. They are located under html/ in the documentation directory.
lircd(8), mode2(1), smode2(1), xmode2(1), irrecord(1), irw(1), http://www.lirc.org.
irsend 0.9.0-pre1 October 2010 IRSEND(1)
01-09-2016
so I might have missed some points completely hence is my confusion.