Concatenate Variables in Linux Shell
In Linux, variables can be concatenated to commands using Shell. The specific method depends on the type of Shell you are using.
In most common shells, various ways can be used to concatenate variables into commands.
- To concatenate variables using double quotation marks: Wrap the variable with double quotation marks and prefix it with a dollar sign ($) to reference the variable.
variable="world"
echo "Hello $variable"
Output result:
Hello world
- When using single quotes to concatenate variables, the variables will not be interpreted but instead will be directly outputted.
variable="world"
echo 'Hello $variable'
Output result:
Hello $variable
- To concatenate variables using parenthesis: you can enclose the variables in parenthesis and then add a dollar sign before the variable.
variable="world"
echo "Hello ${variable}"
Output results:
Hello world
It is important to note that the above methods can concatenate variables at any position in the command, as long as the variables are placed in the correct position.
In addition, you can use special characters in Shell to concatenate variables, for example, using quotes followed by a dot to join strings (only applicable to Bash and some other Shells).
variable1="Hello"
variable2="world"
result="${variable1} ${variable2}"
echo $result
Output result:
Hello world
In summary, when concatenating variables to a command using Shell, you can use double quotes, single quotes, parentheses, or special characters. Choose the appropriate method based on your specific needs and the type of Shell being used.
