Can anyone please tell me some external commands of Linux? Also explain type command in Linux?
Thanks
5  7182  RedSon 5,000
Recognized Expert Expert
You need to define "external commands"; Also define "type command". No one knows what you are talking about.
To my understanding external commands are those which are not built-in to bash or think of these are hard-coded in to bash. Like, ifconfig, /bin/echo (mere echo is a built in command of bash). Assuming this is what you mean by external command, most of the commands we use are external commands. The internal command examples are 'if','while' etc..
Am i right with my assumption? :D
In my text book of Linux I have read that- There are two types of command in Linux namely Internal and external command. Internal commands are those commands that are automatically loaded into the system memory as soon as the system starts up. These commands will be available as long as the system is kept on like cp, mv, mkdir etc.
External commands are those that are available on a floppy/hard drive and are loaded in the memory of the computer when specially asked for.
my question was that can anyone tell me name of some external commands.
My another question was related to type command. type command followed by the command tell you the type of the command. for example--
$ type cat
cat is hashed (/bin/cat)
can anyone explain the output of this command as I found no manual entry for this command in ubuntu-9.0.4 system?
thanks.
 RedSon 5,000
Recognized Expert Expert
Your book is not very clear. There is only one type of command, it's a binary application. Those "commands" like "man", "cat", "type", "which", "more", "less" and others are just command line applications that people wrote. The reason you can use them easily is that the distributor of your Linux version (ubuntu) put those applications in a special directory that is "on the path".
The "path" is a environment variable that tells the system what file/folder paths to search when trying to find the name of an application that you typed on the command line.
When you type "cat" your shell knows that it should actually execute /bin/cat because /bin is on the path. When you type "type cat" the bash shell is telling you how each name (cat in this case) would be interpreted if used as a command name.
If you want to use a command that is not on the path then you need to specify the full name of it. Example: /home/username/myapplication.b in or whatever it's called. This assumes that your permissions are set up properly.
There is a difference between bash built-in commands and other commands but that is specific to bash. If you used zsh or some other shell you might have different built-in commands. This also changes given what distro you are running.
1. Some people say: "In unix, Commands are programs and programs are commands". Classifying commands as internal/external doesnot appears much logical to me. This concept dates back to old DOS days which had internal and external commands. So, maybe someone tried putting this analogous to way commands are classified under DOS.
2. man type: http://ss64.com/bash/type.html (?)
Sign in to post your reply or Sign up for a free account.
Similar topics | |
by: Hal Vaughan |
last post by:
I need to be able to run external commands from within a Java program, on
Linux and Windows (and eventually OSX). Under most circumstances there is
no problem, but if the path I specify as part of the command has any spaces
in it, or an argument for the command is a path with a space in it, or if I
redirect the output to a file with a space in the filename, it doesn't work
on Linux. I tried putting the paths in both single and double...
|
by: Avi Kak |
last post by:
Is there a Python function in any of the
standard-distribution modules that does
what the backticks do in Perl?
I want to run an external command and I'd
like its output to be captured directly
in my Python script in the form of a string
object.
The function os.system() or any of the
|
by: James Colannino |
last post by:
Hey everyone. First off, I'm new to the list. I had had a little bit
of experience with Perl before discovering Python. The more Python I
learn, the more I love it :) I just have a quick question to ask. I
know that this is probably a simple question, but I've been googling
around, and partly because I'm not sure exactly what to search for, I've
been unsuccessful at finding an answer. What I'd like to do is be able
to take the output...
|
by: Franck Diastein |
last post by:
Hi,
I'm designing an application, and I would like to be able to receive
external commands... I would like a behavior like eMule, when you click
on an ed2k link, the link is added to eMule, even if this app is running...
How can I handle this behavior in my app ?
TIA
|
by: Scott Emick |
last post by:
I've been trying for some time now to decrypt with GPG from inside vb .net
to no avail. my normal decrypt command goes something like this:
gpg.exe --armor --passphrase-fd 0 <
P:\mis\mfg\NorelcoIBM\etc\foxpassphrase.txt -o
\\fox7\mfg$\Applica\Infomercial\Orders\West\%1 -d
\\www\d$\Inetpub\ftproot\littermaid_west\inbox\%1.PGP
The input file is normally called something.txt.pgp and this command
generates the output file for me...
| | |
by: Tommy B |
last post by:
I'm currently working on a script that I will run when I leave my
computer on at night. It runs external commands like Ad-Aware, Spybot,
AVG, Avast, and the like. The problem is, I want to know how to make it
so that one command starts only after the last one finishes. When I run
them, they end up running all at once! Can someone please tell me if
this is possible? Judging from what I've seen in Python's versitility,
I bet it can...
|
by: saibotorama |
last post by:
What is the Python translation for this Bash statement:
tar cf - "${files}" | bzip2 "$file".tar.bz2
(Ignoring the fact that "tar cjf" also exists...)
In other words, how does one pipe together arbitrary commands?
|
by: khushtarzia |
last post by:
HI,
Can anybody tell me how we can Execute DOS Internal or External commands like DIR, CLS,MD,RD or CHKDSK etc. from VB6?
Thanks
Khushtar Zia
|
by: RoB |
last post by:
Hi all,
I'm coming from the Informix world and I have a customer using DB2
8.2.3 for Linux on Red Hat Enterprise ES.
The customer is performing filesystem backups of the containers etc
every night but they are not shutting down the database server while
doing this. I only assume that this most likelly would leave an
inconsistant backup image as there is nothing assuring that the
modified pages in the buffer pool get written to disk...
|
by: marktang |
last post by:
ONU (Optical Network Unit) is one of the key components for providing high-speed Internet services. Its primary function is to act as an endpoint device located at the user's premises. However, people are often confused as to whether an ONU can Work As a Router. In this blog post, we’ll explore What is ONU, What Is Router, ONU & Router’s main usage, and What is the difference between ONU and Router. Let’s take a closer look !
Part I. Meaning of...
|
by: Hystou |
last post by:
Most computers default to English, but sometimes we require a different language, especially when relocating. Forgot to request a specific language before your computer shipped? No problem! You can effortlessly switch the default language on Windows 10 without reinstalling. I'll walk you through it.
First, let's disable language synchronization. With a Microsoft account, language settings sync across devices. To prevent any complications,...
| | |
by: tracyyun |
last post by:
Dear forum friends,
With the development of smart home technology, a variety of wireless communication protocols have appeared on the market, such as Zigbee, Z-Wave, Wi-Fi, Bluetooth, etc. Each protocol has its own unique characteristics and advantages, but as a user who is planning to build a smart home system, I am a bit confused by the choice of these technologies. I'm particularly interested in Zigbee because I've heard it does some...
|
by: agi2029 |
last post by:
Let's talk about the concept of autonomous AI software engineers and no-code agents. These AIs are designed to manage the entire lifecycle of a software development project—planning, coding, testing, and deployment—without human intervention. Imagine an AI that can take a project description, break it down, write the code, debug it, and then launch it, all on its own....
Now, this would greatly impact the work of software developers. The idea...
|
by: isladogs |
last post by:
The next Access Europe User Group meeting will be on Wednesday 1 May 2024 starting at 18:00 UK time (6PM UTC+1) and finishing by 19:30 (7.30PM).
In this session, we are pleased to welcome a new presenter, Adolph Dupré who will be discussing some powerful techniques for using class modules.
He will explain when you may want to use classes instead of User Defined Types (UDT). For example, to manage the data in unbound forms.
Adolph will...
|
by: conductexam |
last post by:
I have .net C# application in which I am extracting data from word file and save it in database particularly. To store word all data as it is I am converting the whole word file firstly in HTML and then checking html paragraph one by one.
At the time of converting from word file to html my equations which are in the word document file was convert into image.
Globals.ThisAddIn.Application.ActiveDocument.Select();...
|
by: TSSRALBI |
last post by:
Hello
I'm a network technician in training and I need your help.
I am currently learning how to create and manage the different types of VPNs and I have a question about LAN-to-LAN VPNs.
The last exercise I practiced was to create a LAN-to-LAN VPN between two Pfsense firewalls, by using IPSEC protocols.
I succeeded, with both firewalls in the same network. But I'm wondering if it's possible to do the same thing, with 2 Pfsense firewalls...
|
by: adsilva |
last post by:
A Windows Forms form does not have the event Unload, like VB6. What one acts like?
| | |
by: 6302768590 |
last post by:
Hai team
i want code for transfer the data from one system to another through IP address by using C# our system has to for every 5mins then we have to update the data what the data is updated we have to send another system
| |
