How do you write an if else condition in shell script?

How do you write an if else condition in shell script?

Their description with syntax is as follows:

1. if statement. This block will process if specified condition is true.
2. if-else statement.
3. if..elif..else..fi statement (Else If ladder)
4. if..then..else..if..then..fi..fi..(Nested if)
5. Syntax: case in Pattern 1) Statement 1;; Pattern n) Statement n;; esac.
6. Example 2:

What is if test in shell script?

The if in a Bash script is a shell keyword that is used to test conditions based on the exit status of a test command. An exit status of zero, and only zero, is a success, i.e. a condition that is true. Any other exit status is a failure, i.e. a condition that is false.

How do you end an if statement in shell script?

2 Answers. Try replacing the last line ( endif ) with fi , which is the correct token to close an if statement. Also, replace ($2 == “both”) with the correct [ $2 == “both” ] . Note the quotes around $2 , the spaces after [ and before ] and the ; before the then .

How do I run an if statement in Linux?

The if statement starts with the if keyword followed by the conditional expression and the then keyword. The statement ends with the fi keyword. If the TEST-COMMAND evaluates to True , the STATEMENTS gets executed. If TEST-COMMAND returns False , nothing happens; the STATEMENTS get ignored.

How do you exit a shell script in Linux?

To end a shell script and set its exit status, use the exit command. Give exit the exit status that your script should have. If it has no explicit status, it will exit with the status of the last command run.

What does fi mean in Linux?

fi statement is the fundamental control statement that allows Shell to make decisions and execute statements conditionally.

What is in if in bash?

Bash If-Else Statement Syntax If the condition evaluates to true , the if block code is executed, and if the condition evaluates to false then the else block code is executed. Note: The if block only gets executed if the condition evaluates to true. We have to finish the if statement with the fi keyword.

How do you fail a shell script?

One approach would be to add set -e to the beginning of your script. That means (from help set ): -e Exit immediately if a command exits with a non-zero status. So if any of your commands fail, the script will exit.

What’s the difference between a console and a shell?

Technically the Console is the device and the Terminal is now the software program inside the Console. In the software world a Terminal and a Console are, for all intents, synonymous. A shell is the program that the terminal sends user input to. The shell generates output and passes it back to the terminal for display.

What’s the difference between a terminal and a shell in Linux?

In Linux, a terminal window is the emulation of a console, contained in a GUI window. It is the CLI you type your text in, and this input is read by the shell you’re using. There are many types of shells (e.g. bash, dash, ksh88) and terminals (e.g. konsole, gnome). (3) For an explanation on pseudo terminals, view this.

What’s the difference between a console and a script?

PowerShell is a scripting language, a terminal, a shell, and a backend all at once. Windows Terminal is just a terminal. Hence, the first question is valid. Earlier versions of ConEmu also did not come with PowerShell Core pre-configured in them. And Cygwin is a great alternative to WSL for running Bash if Bash is all one wants.

What’s the difference between a console and a pseudo terminal?

Pseudo Terminals are terminal emulators or software interfaces that emulate terminals. They pretend to be terminals like the ones above. *Nix systems have long had a pseudo-terminal (PTY) infrastructure and now Windows as a pseudoconsole (ConPTY) as well.