LINUX:TR command Explanation

The TRTR command can replace, compress, and delete characters from standard input

Grammar

TR Options (SET1 SET2)

Options

- C or--complerment: Supersedes all characters that are not part of the first character set;-D or--delete: Deletes all characters belonging to the first character set;-S or--squeeze-  Repeats: the consecutive repeating character is represented by a single character;-T or--truncate-set1: First remove the characters from the first character set that are more than the second character set.

Parameters

SET1: Specifies the original character set to be converted or deleted.

When performing a conversion operation, the target character set of the transformation must be specified using the parameter "SET2".

However, the parameter "SET2" is not required when performing the delete operation;

SET2: Specifies the target character set to convert to.

Instance

Converts an input character from uppercase to lowercase

 Last|TR 'A- z' 'A- z' 'A- z'And'A- z'are all collections such as:'abd-}'、'BB.,'、'a-de-h'、'a-c0-9'All belong to the collection, can be used in the collection'\ n'、'\ t', you can use other ASCII characters.

Using TR to delete characters

cat/etc/passwd | Tr-d ': '

To convert a tab to a space:

Cat TR ' \ t ' ' '

A character set complement that deletes all characters from the input text that are not in the complement:

Echo 1 2 c*/cc34tr'0-9 \ n' results:12  34 In this example, the complement contains a number 0~9, a space, and a newline character \ n, so it has not been deleted and all other characters have been deleted.

To compress characters with TR, you can compress the repeated characters in the input:

Echo " Thissss is a text linnnnnnne. " TR ' SN ' This was a text line.

Clever use of TR to do number addition operation:

Echo 1 2 3 4 5 6 7 8 9 Xargs Echo $[$ (tr'\ n'+' ) 0 ]

Remove the ' ^m ' character from the Windows file ' cause ':

Cat file TR " \ r " " \ n "

Cat file TR " \ r "

The character classes you can use:

[: Alnum:]: Letters and Numbers [: Alpha:]: letter [: Cntrl:]: Control (nonprinting) character [:d Igit:]: Number [: Graph:]: graphic character [: Lower:]: lowercase letter [:p rint:]: printable character [:p UNCT:] : Punctuation [: Space:]: blank character [: Upper:]: Uppercase [: xdigit:]: hexadecimal character

How to use

TR ' [: Lower:] ' ' [: Upper:] '

LINUX:TR command Explanation