[root@centos7 ~]# cat a.txt abcdefg [root@centos7 ~]# [root@centos7 ~]# sed -e 's#\(.\)#\1\n#g' a.txt a b c d e f g [root@centos7 ~]# [root@centos7 ~]# cat a.txt|while read line ; do echo $line | sed -e 's#\(.\)#\1\n#g' ;done a b c d e f g [root@centos7 ~]#