#在test文件第四行的下一行插入testfour
[oracle@ctp ~]$ sed -e 4a\testfour test
one
two
three
four
testfour
five
six
#在test文件第四行的上一行插入testfour
[oracle@ctp ~]$ sed -e 4i\testfour test
one
two
three
testfour
four
five
six
原文：https://www.cnblogs.com/joeshang/p/10503223.html