You can use command called fold. It wrap each input line (or lines from file) to fit in specified width. Width can be specified in columns or bytes size. By default Wrap input lines in each FILE from standard input (keyboard ), writing to standard output (screen).
fold -b size -w width file-name
- -b : Use bytes rather than columns
- -w : use WIDTH columns instead of 80 (which is default)
$ fold -w 40 file.txt
$ cat file.txt | grep something | fold -b 20