adding && \ to each line on a text file except last line

问题

I'm trying to add && \ on end of each line on a text file except the last line.

Sample input:

ps 
mkdir repo 
cd repo/ 
touch file1.txt 

Expected output:

ps && \
mkdir repo && \
cd repo/ && \
touch file1.txt 

First attempt

I tried this, but it outputs && \ on each line including the final line:

awk '{print $0"&& \\"}' RS="\r*\n\r*"

Second attempt

I tried using sed:

sed '1s/^//;$!s/$/"&&" \\/;$s/$//'

This seems to add extra newlines:

 ps
 && \
mkdir repo
 && \
cd repo/
 && \
touch file1.txt

回答1:

You could use sed for something that simple:

printf "line 1\nLine 2\nLine 3\n" | sed '$ ! s/$/ \&\& \\ /'

Output

line 1 && \ 
Line 2 && \ 
Line 3

来源：https://stackoverflow.com/questions/60319865/adding-to-each-line-on-a-text-file-except-last-line