Shell programming: shell's method of reading files by row

Shell programming learning method: shell reading files by Line Method 1 :----------------------------------------------------------------------------#! /Bin/bash while read linedo echo $ linedone <filename (file to be read) ---------------------------------------------------------------------------- Statement 2: Prepare :----------------------------------------------------------------------------#! /Bin/bash cat filename (file to be read) | while read linedo echo $ linedone into Statement 3: Waiting for line in 'cat filename (file to be read) 'Do echo $ linedone rows Description: for row-by-row reading and while row-by-row reading are different, for example: $ cat file111122223333 4444 $ cat file | while read line; do echo $ line; done111122223333 4444 555 $ for line in $ (<file); do echo $ line; done11112233334444555