[Linux 常見問題] How to output a multiline string in Bash?

Source From Here
Question
How can I output a multipline string in Bash without using multiple echo calls like so:

view plaincopy to clipboardprint?

1. echo "usage: up [--level | -n ][--help][--version]"  
2. echo   
3. echo "Report bugs to: "  
4. echo "up home page: "  

I'm looking for a portable way to do this, using only Bash builtins.

How-To
Here documents are often used for this purpose.

view plaincopy to clipboardprint?

1. cat << EOF  
2. usage: up [--level | -n ][--help][--version]  
3.   
4. Report bugs to:   
5. up home page:  
6. EOF  

They are supported in all Bourne-derived shells including all versions of Bash. Another way is using bash built-in command read:

view plaincopy to clipboardprint?

1. # -d DELIM : The first character of DELIM is used to terminate the input line, rather than newline.  
2. read -d '' help <<- EOF  
3.   usage: up [--level | -n ][--help][--version]  
4.   
5.   Report bugs to:  
6.   up home page:  
7. EOF   
8.   
9. echo "$help"  

This message was edited 3 times. Last update was at 15/10/2016 12:23:02