Linuxteaching
- How do you do if then else in bash?
- How do you write multiple if else statements in shell script?
- What is else if in bash?
- How does Elif work in bash?
- What is if in shell scripting?
- Which bash version am I using?
- What is $? In Bash?
- Is else mandatory in bash?
- How do I run a bash script?
- How do I get input in bash?
- How do I check if an argument is empty in bash?
- What is in a bash script?
How do you do if then else in bash?
The if statement starts with the if keyword followed by the conditional expression and the then keyword. The statement ends with the fi keyword. If the TEST-COMMAND evaluates to True , the STATEMENTS gets executed. If TEST-COMMAND returns False , nothing happens, the STATEMENTS gets ignored.
How do you write multiple if else statements in shell script?
To use multiple conditions in one if-else block, then elif keyword is used in shell. If expression1 is true then it executes statement 1 and 2, and this process continues. If none of the condition is true then it processes else part.
What is else if in bash?
The elif (else if) is used for multiple if conditions. In case if the first condition goes false then check another “if” conditions. In the following example, we are taking input from the user and display corresponding statements. Use “if” condition to check if the marks are greater or equal to 80.
How does Elif work in bash?
The elif (else if) is used for multiple if conditions. In case one if the condition goes false then check another if conditions. For example, input the marks of a student and check if marks are greater or equal to 80 then print “Very Good”. If marks are less than 80 and greater or equal to 50 then print 50 and so on.
What is if in shell scripting?
Conditions in Shell Scripts
An if-else statement allows you to execute iterative conditional statements in your code. We use if-else in shell scripts when we wish to evaluate a condition, then decide to execute one set between two or more sets of statements using the result.
Which bash version am I using?
To find my bash version, run any one of the following command: Get the version of bash I am running, type: echo "$BASH_VERSION" Check my bash version on Linux by running: bash --version. To display bash shell version press Ctrl + x Ctrl + v.
What is $? In Bash?
$? is a special variable in bash that always holds the return/exit code of the last executed command. You can view it in a terminal by running echo $? . Return codes are in the range [0; 255]. A return code of 0 usually means everything is ok.
Is else mandatory in bash?
Note that the “ELSE” statement is optional, if you omit it, nothing will be executed if the condition evaluates to false. Note : you need to separate the condition from the squared brackets with a space, otherwise you might get a syntax error.
How do I run a bash script?
Make a Bash Script Executable
- 1) Create a new text file with a . sh extension. ...
- 2) Add #!/bin/bash to the top of it. This is necessary for the “make it executable” part.
- 3) Add lines that you'd normally type at the command line. ...
- 4) At the command line, run chmod u+x YourScriptFileName.sh. ...
- 5) Run it whenever you need!
How do I get input in bash?
Example 1:
- #!/bin/bash.
- # Read the user input.
- echo "Enter the user name: "
- read first_name.
- echo "The Current User Name is $first_name"
- echo.
- echo "Enter other users'names: "
- read name1 name2 name3.
How do I check if an argument is empty in bash?
To find out if a bash variable is empty:
- Return true if a bash variable is unset or set to the empty string: if [ -z "$var" ];
- Another option: [ -z "$var" ] && echo "Empty"
- Determine if a bash variable is empty: [[ ! -z "$var" ]] && echo "Not empty" || echo "Empty"
What is in a bash script?
A Bash script is a text file containing a series of commands. Any command that can be executed in the terminal can be put into a Bash script. Any series of commands to be executed in the terminal can be written in a text file, in that order, as a Bash script.
