http://www.gnu.org/software/coreutils/manual/coreutils.html#nl-invocation
The beginnings of the sections of logical pages are indicated in the input file by a line containing exactly one of these delimiter strings:
‘\:\:\:’
start of header;
‘\:\:’
start of body;
‘\:’
start of footer.
我的例子：
[root@localhost ~]# cat test01.txt \:\:\: header--01 \:\: body--0001-line1 body--0001-line2 \: footer--01 \:\:\: header--02 \:\: body--0002-line1 body--0002-line2 \: footer--02 [root@localhost ~]# nl test01.txt header--01 1 body--0001-line1 2 body--0001-line2 footer--01 header--02 1 body--0002-line1 2 body--0002-line2 footer--02 [root@localhost ~]#
