cut is used to process an object in each behavior, and this mechanism is the same as sed.
Cut accepts three positioning methods:
1）byte： -b
2）characters： -c
3）fields： -d
eg: Extract the bytes of 3, 4, 5, 9:cut -b 3-5,9
Note: If the cut command uses the -b option, all positionings after -b will be sorted from small to large when executing it, and then extracted it. The order cannot be reversed.
-3 means from the first byte to the third byte;
3- Indicates from the third byte to the end.
For Chinese extraction, -c will be in characters and the output is normal; -b will be calculated in bytes (8-bit binary).
When multibyte characters are encountered, the -n option is used, and the multibyte characters will not be disassembled.cut -nb 1,2,3
For non-fixed format information, a domain is required. Before, you need to set the spacer and then extract the number of fields.
cut -d : -f 1
-d sets the spacer to:, -f 1 is to extract the first field.
Note: How to identify spaces and tab characters if you encounter them?
First check whether this space consists of spaces or tab characters:
cat tab_space.txt sed -n l tab_space,txt
If it is a tab position (TAB), it will be displayed, and if it is a space, it will be displayed as it is. (l after n in sed is L in lowercase)
cut -d What symbol is used to represent tabs or spaces?
cut -d The default interval is tab characters and can be omitted. If space is set as a spacer, cut -d ' ' -f 4
(There must be a space in two single quotes)
And you can only set one space after -d, and multiple spaces are not allowed. The allowable spacer character for cut is a character.
Summarize
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