Learn Linux Shell Scripting - Fundamentals of Bash 4.4

Here documents

The final concept we'll introduce in this chapter is the here document. Here documents, also called heredocs, are used to supply input to certain commands, slightly different to stdin redirection. Notably, it is an easy way to give multiline input to a command. It works with the following syntax:

cat << EOFinputmore inputthe last inputEOF

If you run this in your Terminal, you'll see the following:

reader@ubuntu:~/scripts/chapter_12$ cat << EOF> input> more input> the last input> EOFinputmore inputthe last input

The << syntax lets Bash know you want to use a heredoc. Right after that, you're supplying a delimiting identifier. This might seem complicated, but it really means that you supply a string that will terminate the input. ...