The most used command to displays the environment variables is printenv . If the name of the variable is passed as an argument to the command, only the value of that variable is displayed. If no argument is specified, printenv prints a list of all environment variables, one variable per line.
How do I get the value of a variable in bash?
Now, using the echo command we can simply display its value on the terminal as follows:
- $ var_a=100. $ echo $var_a.
- $ var_b=” bash programming echo variable” $ echo $var_b.
- $ var_A=”hellofriends” $ var_B=50. $ echo $var_A$var_B.
- $ var1=$(date) $ var2=$(hostname) $ echo “the date is $var1 @ computer name is $var2”
How do you echo the value of a variable?
To display the value of a variable, either use echo or printf command as follows:
- echo $varName # not advisable unless you know what the variable contains.
- echo “$varName”
- printf “%sn” “$varName”
How do you print a variable value in Unix?
To Print the value of above variables, use echo command as shown below :
- # echo $HOME. # echo $USERNAME.
- $ cat myscript.
- #!/bin/bash. # display user information from the system. …
- $ echo “The cost of the item is $15” …
- $ echo “The cost of the item is $15” …
- var1=10. …
- $ cat test3. …
- Running the script produces the following output:
How do you set a variable in bash?
The easiest way to set environment variables in Bash is to use the “export” keyword followed by the variable name, an equal sign and the value to be assigned to the environment variable.
How do you print a variable in linux?
Sh, Ksh, or Bash shell user type the set command. Csh or Tcsh user type the printenv command.
How do you echo a variable in shell?
For example, Declare a variable of x and assign its value=10. Note: The ‘-e’ option in Linux acts as interpretation of escaped characters that are backslashed.
…
echo Options.
| Options | Description |
|---|---|
| -n | do not print the trailing newline. |
| -e | enable interpretation of backslash escapes. |
| b | backspace |
| \ | backslash |
How do bash scripts work?
A Bash script is a plain text file which contains a series of commands. These commands are a mixture of commands we would normally type ouselves on the command line (such as ls or cp for example) and commands we could type on the command line but generally wouldn’t (you’ll discover these over the next few pages).
How do I export a variable in Linux?
To make an environment persistent for a user’s environment, we export the variable from the user’s profile script.
- Open the current user’s profile into a text editor. vi ~/.bash_profile.
- Add the export command for every environment variable you want to persist. export JAVA_HOME=/opt/openjdk11.
- Save your changes.
How do you set a variable in UNIX?
Set environment variables on UNIX
- At the system prompt on the command line. When you set an environment variable at the system prompt, you must reassign it the next time you log-in to the system.
- In an environment-configuration file such as $INFORMIXDIR/etc/informix.rc or .informix. …
- In your .profile or .login file.
How do you create a variable in Linux?
Variables 101
To create a variable, you just provide a name and value for it. Your variable names should be descriptive and remind you of the value they hold. A variable name cannot start with a number, nor can it contain spaces. It can, however, start with an underscore.
How do I export a variable in shell?
Exporting shell variables (export shell command)
You can use the export command to make local variables global. To make your local shell variables global automatically, export them in your . profile file. Note: Variables can be exported down to child shells but not exported up to parent shells.
How do I change the PATH variable in Linux?
To make the change permanent, enter the command PATH=$PATH:/opt/bin into your home directory’s . bashrc file. When you do this, you’re creating a new PATH variable by appending a directory to the current PATH variable, $PATH . A colon ( : ) separates PATH entries.