You can run any program within a shell script without user action by supplying the required input for the interactive program.
EOF operator stands for the end of the file. This means that wherever a compiler or an interpreter encounters this operator, it will receive an indication that the file it was reading has ended.
Insert data into the file without using the echo command.
1 2 3 cat <<EOF > demo.txt hello world EOF
You can also use variables here, cat command will execute variables automatically. To avoid execution automatically, use a special character backslash.
1 2 3 4 cat <<EOF > demo.sh Hello, world whoami=\$HOME EOF
You can use heredoc to create a template like this. Run the following command as an example.
1 2 3 4 5 6 7 8 9 cat <<EOF Usage: <command_name> [option] Description: Your description. Options: -u Update -h Show the help -v Get the tool version -d Show detailed information EOF