[LINUX] [Bash] Redirection of multiple lines to multiple files

--When using Bash, you may want to write a character string with multiple lines of content in a shell script to multiple files. ――At that time, multiple ʻechoor multiple>` are written one after another, and it may become long or duplicates may be noticeable. --Therefore, this time, record the method of writing (redirecting) the contents of multiple lines to multiple files at once.

result

――The contents of the result are shown below. --This is a method using Bash's ** here document ** and ** tee command **.

function multi(){
	#Definition of multi-line strings in here-documents
	cat <<-EOF
		# list data
		aaa bbb ccc
		ddd eee fff
		ggg hhh iii
	EOF
}

#Pass to tee command and write(redirect)Specify the target file
#Because it is non-output/dev/Discard to null.
multi | tee result.txt result.bak.txt > /dev/null

--After writing in any shell file, complete when execution and creation confirmation are possible.

Contents

Utilization of here documents

--Use Here document when defining multiple strings. ――The following two points were conscious at that time. -** <<- to enable indentation. ** ** --Specify this to delete the first tab character and adjust the appearance. -** Put it in the function. ** ** --The written content, whether it is directly specified or a variable, is put in a function and made into a constant. ――It leads to "universality of organizing and using written contents (pipes, etc.)".

Use of tee command

-** Use the ** tee command that outputs and writes at the same time from input. --By doing so, by passing the defined contents to tee, it will output and write to the specified file at the same time. -** * However, since it does not output, pass the contents to / dev / null and do not output **

reference

• tee -Here document
• https://teratail.com/questions/172518