追加命令(命令a) sed '[address] a the-line-to-append' input-file 在第二行后面追加一行(原文这里可能有问题,没有写名行号) [root@sishen ~]# sed '2 a 203,Jack Johnson,Engineer' employee.txt 101,Johnnynynyny Doe,CEO 102,Jason Smith,IT Manager 203,Jack Johnson,Engineer 103,Raj Reddy,Sysad