结果可以从man手册找到
-F参数
-F fs
–field-separator fs
Use fs for the input field separator (the value of the FS predefined variable).
-F参数指定用于分割的字符或者是字符串。
Fields
As each input record is read, gawk splits the record into fields, using the value of the FS variable as the field separator.If FS is a single character, fields are separated by that character. If FS is the null string, then each individual character becomes a separate field.
NF(代表的是被分割后的字段总数)
The variable NF is set to the total number of fields in the input record.
以下字段为例:
| `- 17:0:0:0 sdl 8:176 active ready running
echo '| `- 17:0:0:0 sdl 8:176 active ready running' | awk -F " " '{print $NF}'
结果为:running
echo '| `- 17:0:0:0 sdl 8:176 active ready running' | awk -F " " '{print $(NF-1)}'
结果为:ready