read is a built-in shell command that reads from stdin. See the example below:

$ read war year
WWI 1918
$ ./upp.sh $war $year
Filename: upp.sh
First Argument: WWI
Second Argument: 1918
WWI ended in 1918

read created two variables $war and $year. User assigned the values WWI and 1918. These variables were passed as parameter to the program we created in the previous section.

read command is very handy with files. Create a file called data.txt and add the following line to it.

cold-war 1991

Then run the commands as below:

$ read var < data.txt
$ ./upp.sh $var

Output

Filename: upp.sh
First Argument: cold-war
Second Argument: 1991
WWI ended in 1991