What happens when you start a login shell which files are read and used and why )?
When Bash is invoked as an interactive login shell, or as a non-interactive shell with the –login option, it first reads and executes commands from the file /etc/profile , if that file exists. After reading that file, it looks for ~/. bash_profile , ~/. bash_login , and ~/.
What is the difference between an interactive shell and a non-interactive shell?
Simply put: Interactive shell require user input, while non-interactive shell are run by scripts and don’t require user inputs.
What is the difference between ETC profile and ~/ Bash_profile?
/etc/profile is global configuration for login shells (interactive or not), ~/. bash_profile is per-user configuration for login shells, and ~/. bashrc is configuration for interactive non-login shells.
What is the difference between login shell and non login shell?
Non Login Shell is the shell, which is started by the login shell. For example, A shell which you started from another shell or started by a program etc. A non login shell executes the following script to set the shell environment.
What are shell configuration files Why do we need it?
Bash Shell Configuration Files To configure Bash to use our custom settings we need to configure various configuration files that are used. Some of these files are only executed at “login”, others are executed each time a new instance of your Bash shell is started.
What is the difference between bash and TCSH?
bash (the Bourne-Again shell) is a superset of sh, so any script written for sh should work fine in bash. However, tcsh is a more advanced version of csh, the C shell.
What is difference between interactive and non-interactive?
Interactive Mode means that you can use the web page like normal navigating. You can type into it, click on links, etc. Non-Interactive Mode means that you cannot use the browser, think of it like the page is read-only. – want a seamless flow in the presentation while showing a web page.
What are interactive shell programs?
An interactive shell reads commands from user input on a tty. Among other things, such a shell reads startup files on activation, displays a prompt, and enables job control by default. The user can interact with the shell. A shell running a script is always a non-interactive shell.
What is profile file in Linux?
A profile file is a start-up file of an UNIX user, like the autoexec. bat file of DOS. When a UNIX user tries to login to his account, the operating system executes a lot of system files to set up the user account before returning the prompt to the user.
What is the file type of ETC profile?
The /etc/profile File The /etc/profile contains Linux system wide environment and other startup scripts. Usually the default command line prompt is set in this file. It is used for all users logging in to the bash, ksh, or sh shells.
What is a login shell?
A login shell is a shell given to a user upon login into their user account. This is initiated by using the -l or –login option, or placing a dash as the initial character of the command name, for example invoking bash as -bash. Sub shell. Simulating an initial login shell with bash -l or sh -l.
What are login shell configuration files?
Bash Configuration Files and their Location This is a “System wide” initialisation file that is executed during login. This file provides initial environment variables and initial “PATH” locations. This again is a “System Wide” initialisation file. This file is executed each time a Bash shell is opened by a user.
How does Bash work in interactive login shell?
In an interactive login shell, Bash first looks for the /etc/profile file. If found, Bash reads and executes it in the current shell. As a result, /etc/profile sets up the environment configuration for all users. Similarly, Bash then checks if .bash_profile exists in the home directory.
What is the purpose of bash_profile?
Significance of .bash_profile The .bash _ profile file contains commands for setting environment variables. Consequently, future shells inherit these variables. In an interactive login shell, Bash first looks for the /etc/profile file. If found, Bash reads and executes it in the current shell.
How does Bash work?
“When bash is invoked as an interactive login shell, or as a non-interactive shell with the –login option, it first reads and executes commands from the file /etc/profile, if that file exists.
What is the difference between login and non-login modes in Bash?
Bash provides the option of two modes in an interactive shell, i.e., login and non-login. When we log in to a system using ssh, we get an interactive login shell. This shell reads startup files when invoked. However, when we invoke a new shell on an already logged-in shell, we get an interactive, non-login shell.