Linux shell removes line breaks (multiple lines of content are displayed on one line) & Delete empty lines

Remove line breaks (multiple lines of content are displayed on one line):

1.sed-e ': A; N;s/\n//;ta ' filename

2. In VI, using:%s/\n//g

3.cat filename |xargs Echo

and cat Filename|xargs behavior is the same, xargs default is the result of the previous command to print output, the content of multiple lines is displayed on one line, the simplest way

Delete the ^m symbol (CTRL + V, then ctrl+m)

1.sed-e ' s/^m//g ' filename

2. In VI, using:%s/^m//g

"G" full text replacement, no "G" is only matched to replace the first match, sed ' 1,2s/ab/cd/' to replace the 1th, 2 line ab to CD

To delete an empty line character:
1.cat filename|tr-s ' \ n '
2.sed '/^$/d ' filename
3.awk ' {if ($0!= "") print} ' filename

4.grep-v "^$" filename

Linux shell removes line breaks (multiple lines of content are displayed on one line) & Delete empty lines