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1. Top results related to what is a shell script in linux operating system

   • What does "read -p" do in a linux shell script?

     Top Answer

     Answered Apr 13, 2017 · 19 votes

     First off, the structure <command> -<option> means that you want to execute <command> using the option corresponding to <option>. A - after a command means that the following letter is an option. Most commands have several options you can use. Options are usually defined using either a single letter or a couple of words separated by -.

     Side Note: For options that are a couple of words rather than a single letter, often it will use two minus signs -- instead of one, signifying that it is a "long named" option.

     So, using the read -p example, this means you want to execute read using the p option, which stands for prompt.

     Now, sometimes an option will require an argument. In your examples, the options to useradd have arguments. Arguments are usually defined like <command> -<option> [argument]. So, in the useradd example, $group is an argument for the option g.

     Now for the commands themselves:

     read

     is a bash built-in (not a POSIX shell command) that reads from standard input.

     • The -p option makes it read as a prompt, meaning it doesn't add a trailing newline before trying to read input.

     if

     checks the return status of the test command (in this case id -u $username >/dev/null 2>&1)

     • If the return status is 0, the then part is executed

     id

     prints user groups and ids

     • The -u option "prints only the effective user ID".
     • >/dev/null 2>&1 redirects standard input and standard error to /dev/null, meaning they do not get printed to the terminal.

     useradd

     creates a new user

     • -g sets the initial group for the user
     • -s sets the name of the user's login shell
     • -d sets the name of the user's login directory
     • -m says to create the user's home directory if it does not exist.
     • -p defines the user's encrypted password.

     For future reference, you can look up commands in the linux manual pages by doing man <command> on the command line. These manual pages tell you what a command does, as well as explaining all of its options.

     Bash built-ins like read are all on a single man page that is not the easiest thing to use. For those I find googling them easier. Usually http://ss64.com/ will come up in the results, which contains the info from the bash built-ins man page, but separated into different pages by command. I find this much easier to use.

     Check all answers on Stack Overflow

     1/5

   • What is Linux Operating System

     The Linux Operating System is a type of operating system that is similar to Unix, and it is built upon the Linux Kernel. The Linux Kernel is like the brain of the operating system because it manages how the computer interacts with its hardware and resources. It makes sure everything works smoothly and efficiently. But the Linux Kernel alone is not enough to make a complete operating system. To create a full and functional system, the Linux Kernel is combined with a collection of software packages and utilities, which are together called Linux distributions. These distributions make the Linux Operating System ready for users to run their applications and perform tasks on their computers securely and effectively. Linux distributions come in different flavors, each tailored to suit the specific needs and preferences of users.

     What is Linux

     Linux is a powerful and flexible family of operating systems that are free to use and share. It was created by a person named Linus Torvalds in 1991. What’s cool is that anyone can see how the system works because its source code is open for everyone to explore and...

     Check all answers on Geeksforgeeks

     2/5

   • What is Linux Operating System

     The Linux Operating System is a type of operating system that is similar to Unix, and it is built upon the Linux Kernel. The Linux Kernel is like the brain of the operating system because it manages how the computer interacts with its hardware and resources. It makes sure everything works smoothly and efficiently. But the Linux Kernel alone is not enough to make a complete operating system. To create a full and functional system, the Linux Kernel is combined with a collection of software packages and utilities, which are together called Linux distributions. These distributions make the Linux Operating System ready for users to run their applications and perform tasks on their computers securely and effectively. Linux distributions come in different flavors, each tailored to suit the specific needs and preferences of users.

     What is Linux

     Linux is a powerful and flexible family of operating systems that are free to use and share. It was created by a person named Linus Torvalds in 1991. What’s cool is that anyone can see how the system works because its source code is open for everyone to explore and...

     Check all answers on Geeksforgeeks

     3/5

   • What is Linux Operating System

     The Linux Operating System is a type of operating system that is similar to Unix, and it is built upon the Linux Kernel. The Linux Kernel is like the brain of the operating system because it manages how the computer interacts with its hardware and resources. It makes sure everything works smoothly and efficiently. But the Linux Kernel alone is not enough to make a complete operating system. To create a full and functional system, the Linux Kernel is combined with a collection of software packages and utilities, which are together called Linux distributions. These distributions make the Linux Operating System ready for users to run their applications and perform tasks on their computers securely and effectively. Linux distributions come in different flavors, each tailored to suit the specific needs and preferences of users.

     What is Linux

     Linux is a powerful and flexible family of operating systems that are free to use and share. It was created by a person named Linus Torvalds in 1991. What’s cool is that anyone can see how the system works because its source code is open for everyone to explore and...

     Check all answers on Geeksforgeeks

     4/5

   • what is the best way to start a script in boot time on linux

     Top Answer

     Answered Jul 06, 2023 · 9 votes

     There are a couple of ways to achieve this, but you will need root privileges for any the following. To get root, open a terminal and run the command:

     sudo su-

     and the command prompt will change to '#' indicating that the terminal session has root privileges.

     Alternative #1. Add an initscript

     Create a new script in /etc/init.d/myscript:

     vi /etc/init.d/myscript-

     (Obviously it doesn't have to be called "myscript".) In this script, do whatever you want to do. Perhaps just run the script you mentioned:

     #!/bin/sh/path/to/my/script.sh-

     Make it executable:

     chmod ugo+x /etc/init.d/myscript-

     Configure the init system to run this script at startup:

     update-rc.d myscript defaults-

     Alternative #2. Add commands to /etc/rc.local

     vi /etc/rc.local-

     with content like the following:

     # This script is executed at the end of each multiuser runlevel/path/to/my/script.sh || exit 1 # Added by meexit 0-

     Alternative #3. Add an Upstart job

     Create /etc/init/myjob.conf:

     vi /etc/init/myjob.conf-

     with the following content:

     description "my job"start on startuptaskexec /path/to/my/script.sh

     BTW:

     You don't need to be root if you can edit your crontab (crontab -e) and create an entry like this:

     @reboot /path/to/script.sh-

     This way, you can run it as a regular user. @reboot just means it's run when the computer starts up (not necessarily just when it's rebooted).

     Check all answers on Stack Overflow

     5/5

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2. www.geeksforgeeks.org › introduction-linux-shellIntroduction to Linux Shell and Shell Scripting - GeeksforGeeks

   www.geeksforgeeks.org › introduction-linux-shell

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   Apr 16, 2024 · A shell script comprises the following elements – Shell Keywords – if, else, break etc. Shell commands – cd, ls, echo, pwd, touch etc. Functions; Control flow – if..then..else, case and shell loops etc. Why do we need shell scripts? There are many reasons to write shell scripts: To avoid repetitive work and automation

3. www.techtarget.com › definition › shell-scriptWhat is a Shell Script and How Does it Work? - TechTarget

   www.techtarget.com › definition › shell-script

   TechTarget Contributor. A shell script is a text file that contains a sequence of commands for a UNIX -based operating system. It is called a shell script because it combines a sequence of commands, that would otherwise have to be typed into the keyboard one at a time, into a single script.

4. People also ask

   What is shell scripting in Linux?

   • Shell scripting is an important part of process automation in Linux. Scripting helps you write a sequence of commands in a file and then execute them. This saves you time because you don't have to write certain commands again and again. You can perform daily tasks efficiently and even schedule them for automatic execution.

   Shell Scripting for Beginners – How to Write Bash Scripts in Linux

   www.freecodecamp.org/news/shell-scripting-crash-course-how-to-write-bash-scripts-in-linux/

   See all results for this question

   What does a shell script contain?

   • Like other programs, the shell script can contain parameters, comments and subcommands that the shell must follow. Users initiate the sequence of commands in the shell script by simply entering the file name on a command line. In the DOS operating system, a shell script is called a batch file.

   What is a Shell Script and How Does it Work? - TechTarget

   www.techtarget.com/searchdatacenter/definition/shell-script

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   What is shell in Linux?

   • Shell accepts human-readable commands from users and converts them into something which the kernel can understand. It is a command language interpreter that executes commands read from input devices such as keyboards or from files. The shell gets started when the user logs in or starts the terminal. Shell is broadly classified into two categories –

   Introduction to Linux Shell and Shell Scripting - GeeksforGeeks

   www.geeksforgeeks.org/introduction-linux-shell-shell-scripting/

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   What is shell scripting used for?

   • Shell scripting is primarily used to automate repetitive system tasks, such as backing up files, monitoring system resources, and managing user accounts. By turning a series of commands into a script, system administrators can save time, increase accuracy, and simplify complex tasks. Who uses shell scripting?

   What is Shell Scripting? | Coursera

   www.coursera.org/articles/what-is-shell-scripting

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5. www.freecodecamp.org › news › shell-scripting-crashShell Scripting for Beginners – How to Write Bash Scripts in ...

   www.freecodecamp.org › news › shell-scripting-crash

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   Mar 31, 2022 · Shell scripting is an important part of process automation in Linux. Scripting helps you write a sequence of commands in a file and then execute them. This saves you time because you don't have to write certain commands again and again. You can perform daily tasks efficiently and even schedule them for automatic execution.

6. www.coursera.org › articles › what-is-shell-scriptingWhat is Shell Scripting? | Coursera

   www.coursera.org › articles › what-is-shell-scripting

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   Nov 29, 2023 · Shell scripting is a text file with a list of commands that instruct an operating system to perform certain tasks. A shell is an interface that interprets, processes, and executes these commands from the shell script. It can be particularly helpful to automate repetitive tasks, helping to save time and reduce human error.

7. www.howtogeek.com › 67469 › the-beginners-guide-toThe Beginner's Guide to Shell Scripting: The Basics - How-To Geek

   www.howtogeek.com › 67469 › the-beginners-guide-to

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   Sep 29, 2015 · Shell scripts allow us to program commands in chains and have the system execute them as a scripted event, just like batch files. They also allow for far more useful functions, such as command substitution. You can invoke a command, like date, and use it's output as part of a file-naming scheme.

   • Author: Yatri Trivedi

8. www.freecodecamp.org › news › bash-scriptingBash Scripting Tutorial – Linux Shell Script and Command Line ...

   www.freecodecamp.org › news › bash-scripting

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   Mar 20, 2023 · Definition of Bash scripting. A bash script is a file containing a sequence of commands that are executed by the bash program line by line. It allows you to perform a series of actions, such as navigating to a specific directory, creating a folder, and launching a process using the command line.

9. adamtheautomator.com › linux-shell-scriptinYour One and Only Linux Shell Scripting Tutorial - ATA Learning

   adamtheautomator.com › linux-shell-scriptin

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   Aug 10, 2021 · A shell is a command language interpreter that executes commands read from the standard input device such as a keyboard or a file to execute programs, create files, etc. Whenever a user opens up the terminal (a console to a shell), the shell issues a command prompt where you’ll type your input.