The read Command
The “read” command can be used to input data from the keyboard, from a file or from a command or set of commands.
The “read” command processes one line at a time.
Input from Where?
While a script is running, a “read” command will, by default, wait for input from <STD_IN> (the keyboard).
read Command Format
The “read” command is followed by one or more arguments. Each argument is interpreted as a variable in which the data received can be placed. There will be a one to one matching of input stream arguments to the “read” command arguments.
Example 1
Example 2: Not enough data input
Example 3: More items in the data input than number of variables
Example 4: Quotes do not have special meaning when they are part of the input data stream
read Command Exit Status
read Data in a While Loop
To read in data line-by-line from a file, and halt when all data has been processed, use the format: