Linux command-tr

Tr

Usage: tr [option]... set1 [set2] replaces, reduces, and/or removes characters from standard input and writes the results to standard output.   -c, -C, --complement         first complement set1   -d, --delete             Delete the contents of the matching set1 , does not replace   -s, --squeeze-repeats     if the character matching the set1  has a continuous    in the input sequence                repetition, which is uniformly shrunk to one character at the time of substitution    -t, --truncate-set1         set1  The length of the first and set2  equal       --help         Display this help message and exit        --version         display version information and exit set  is a set of strings, which can generally be understood by literal means. The parsing sequence is as follows:  \nnn     octal value is nnn  (1  to 3  digits)   \\          anti-Slash   \a         Terminal ringing   \b          backspace   \f         page Break   \n          line break   \r         enter   \t          Horizontal Tab   \v          Vertical Tab    character 1-character 2     all characters   [characters from character 1  to character 2  in ascending increments of characters *]      in set2 , the specified characters are copied continuously until they match the length of the set 1    [characters * Number]     Performs a specified number of copies of a character, if the number of times starts with  0  is treated as an octal number   [:alnum:]     all letters and numbers   [: alpha:]     all letters   [:blank:]     all horizontal white-space characters   [: cntrl:]     all the control characters   [:d igit:]     all the numbers   [:graph:]      InstituteSome printable characters, not including spaces   [:lower:]     all lowercase letters   [:p rint:]     All printable characters, including spaces   [:p unct:]     all punctuation characters   [:space:]     All white space characters arranged horizontally or vertically   [:upper:]     all uppercase letters   [:xdigit:]      All hexadecimal number   [= characters =]     all characters equal to the specified characters are given only in set1  and set2 , without-d  option is not replaced. The-t  option is only possible with replacements. If required set2  will be added to the same length as set1  by adding the original last character at the end. The extra characters in the set2  will be omitted. Only [:lower:]  and [: Upper:] Expand characters in ascending order, and case conversions are represented in pairs in set2  when used for substitution. -s  acts on SET1, neither replace nor delete, otherwise use set2  reduction after substitution or expansion.

Specific examples:Simple substitution character

Echo ABC > ACAT a Abccat a |tr "a" "ABC" Abc[[email protected] mnt]# cat a |tr "a" "ABC" Abc[[email protected] mnt]# CA T a |tr "a" "CJW" Cbc[[email protected] mnt]# cat a |tr "a" "CJW" Cbc[[email protected] mnt]# cat a |tr "a" "s" SBC

You can see that there is a bit limit to modify only the source of the same length string

Replace case

[email protected] mnt]# cat a |tr [a-z] [A-Z][BC This is not possible [[email protected] mnt]# Cat a |tr A-Z A-to-a-kind ABC so OK, or in [] plus ' ' can also

Replace letters with numbers

[[email protected] mnt]# Cat a |tr a-c 2-5234[[email protected] mnt]# cat a |tr A-b 2-523c

It's also a correspondence relationship.

Delete character

[email protected] mnt]# cat a|tr-d ABC

Delete a tab and enter

[[email protected] mnt]# cat ABC |tr-d "\n\t" Abctabtab[[email protected] mnt]# cat ABC |tr-d "\n\t"

delete consecutive repeating letters

[[email protected] mnt]# cat ABCD |tr-s [a-za-z] PS: This is not valid OH: ~ Output is the original string accbbbbdd [[email protected] mnt]# cat ABCD |tr-s ' [a-za-z] ' Acbdok can be [[email protected] mnt]# cat ABCD |tr-s A-ZA-ZACBD so also OK

Delete empty lines

[Email protected] mnt]# echo > Abcd[[email protected] mnt]# cat abcd |tr-d "\ n" [[email protected] mnt]# vim ABCD

There's no space.

tab symbol \011 space, \040

[[email protected] mnt]# cat abcdtab tab TAB PS: Empty between tab [[email Prote CTED] mnt]# cat abcd|tr-s ' \011 ' \040 ' tab tab tab

Linux command-tr