Here in this video we are going to learn about various types of shortcuts and other keys on redhat Linux. So let's start. Here are few shortcuts that you can use on Linux terminal. Control a would allow you to move to the beginning of the line. controlee, a Move to End of the Line control you delete. first line beginning of the line Ctrl, k deletes end of the line.
Control arrow moves left or right by word until represents home directory of a user. You can also use wildcards or globbing that is a wildcard exception, which uses regular expressions. Here on command line. To match zero or more occurrence of a character you can use asterisk symbol For matching any single character, you can use question mark symbol for matching zero or sorry for any range that could be zero to 9027128 ABC you can use square brackets and the range in between or any one of them, you can write those characters one by one. And if you want to match any one character except those in the list, then just place upper arrow symbol on the starting of the string within the square brackets. And then the characters in the brackets are omitted.
Characters in the predefined character class can be matched also. So what does it do these are the keys. For suppose for example, you have a key called alpha and you want to check whether the A occurred once Or more than once, you can check by write a as Craig Andy Asti will check the occurrence of zero or more. So, the occurrence is one times. Similarly, you can write a alpha and the occurrence could be three times actually in alpha there are two times a has occurred and so on. There are more shortcuts.
For example, you can display a string with equal symbol equal command that is a vitally or regularly used in shell scripting to display certain thing information. It is somewhat similar to the printf statement in C and system out print ln in Java, you can use this keyword. You can also use in command line interface, or you just write eco And they shrink. And within this string you can provide any name that is expanded. For example hostname could be provided and just simply write dollar within brackets, the string or argument. So for checking the hostname of this computer, I would write dollar in brackets hostname and it will display the hostname.
Here, a triple w abc.com is the host name of the system. For instance, it is defined whatever we save in it is not the IP address of the computer. You can also use a brace expansion and the curly braces for printing repetitively strings. For example, for if you want to write a file, one to file one file three file file, the simply right Ico file within public Decades races right 135 and so on, it will print those arguments work with we could work with various commands. Just give it a try. There are very variables, you can insert a variable values.
For example if I want to store this string or Hold COMMAND in a single variable or character, you can do so by simply writing $1. Sign $1 is a basic thing that occurs on your screen you don't need to type dollar dollar means, non root user is currently using a system. Suppose I write H i in capital you need to write variable m in capital and assign value on the right side of this name of variable. Suppose my variable name is high, and I want to assign a string. Just write hi equals to the string in codes it will be assigned to it. And if when I want to print that thing on the screen, I will place the variable name within the braces on the code.
We have certain predefined variables on red line Next, the configuration variables and information variables, the configuration value will include p s one, his file size pot editor. So, what does it do? The ps1 configuration variable would allow you to appearance of the bash prompt to change the appearance and anything else. His file size would allow you to number the commands in bash history. Party directory will look for executable files. If you have installed a Java already on any environment either windows Mac or Linux.
You will be familiar with this variable this variable Whether you stole the executable part, the part four where the executable files for JDK or other things are restored and we can define certain other dependencies using this variable. The editor variable is used to configure the default text editor. Then there comes information variables. We are home and he you ID is the very important things. Home variable is used to user's home directory, you can access this thing, use it as a shortcut, or modify the directory. You can use a UID for users effective user ID or UID.
Then there is another useful thing that is called aliasing, or alias. ls is simply a shortcut to other commands. Suppose we have a multiple line of command, a huge command, which contains almost seven or eight arguments on allow a large command on one line to line. And we simply and when we recursively repetitively need to type that command, and we don't want always to type the whole line again and again, you can simply alias that command into a single character or anything of your desired name. Even that alias could be a command. Suppose a init init zero actually shut down your computer on Linux environment.
If you type I nit spaces zero, it will move to run level zero or shutdown state. The initial process the parent process of all the process that we are going to learn later, would be terminated with a zero signal. So I am writing a greeting an alias for unity zero as close the syntax for writing the alias it would be LS al is a space close closes on my given name provided name for this shortcut for that thing. That command equals to, within single quotes, write the command or the with argument or you can omit the argument. Just simply type alias command to see the set of all the aliases which are already set on your system. And ask could be followed by Alias Name or alias value.
And when you type alias close, it will run that thing. We can also create an alias of a command with another commands name. For example, if I want to mess other users on my computers, if I don't want others to use vi editor in my computer, I will alias in it zero to VI. Whenever they type VI, the computer shuts down so they could not use Wi Fi and think computer has crashed. That could be a security point. When you need you can write shell script with a simple syntax.
The first line of a shell script shell script actually contains commands that we use. On Linux terminal or Linux terminal we use a wide range of commands with various arguments to execute different functionalities. We can combine those commands in a format of a programming language or program, which could be a multi line comm program file that is stored as shell So the first line of shell script reads as she ran it begins with a pound symbol or hash symbol, followed by exclamation mark and root symbol forward slash, bin slash bash. This is a root access of four executable where the shell is shells libraries installed. Then it started typing the command. hash symbol the notes command, you can write command with hash or pound symbol.
Ico date and time are this we are were using variable Ico, then we are using ls command ls minus a. You can write different commands. The steps to create a shell script is that create a txt file containing commands she went on the top make the shell script executable by providing the CH mod the permission set permissions and allow any user either yourself or others to execute that file by using the method, either a numeric method or symbolic method that we learned in the previous videos. We will trying it in the practical sessions. Then the third step is to place the script file in a directory on the executable path such as being user local bin, or anywhere else. Or you could also run a script by simply double clicking on a script or on the right leg, press run it will run it is not a difficult thing, but what it is very useful thing shell scripts are very useful these days.
So this was a brief introduction about certain shortcuts, and shell scripting and few other things. So keep Learning keep moving ahead. We will learn more in the coming videos.