head
N rows before reading the file, the default is a front 10, -n digital representation designated
tail
After the n-th row of the output file, the default number 10 lines -n, n row after the specified
representative of real-time -f
N rows before reading the file, the default is a front 10, -n digital representation designated
After the n-th row of the output file, the default number 10 lines -n, n row after the specified
representative of real-time -f