#Bash 的 tr 命令
tr [OPTION]... STRING1 [STRING2]
功能
对标准输入中的字符进行翻译、压缩、删除，然后写入标准输出。
类型
可执行文件（/usr/bin/tr），属于 coreutils。
参数
OPTION选项：-c,-C,--complement- 转换STRING1中不包含的字符-d,--delete- 删除STRING1中的字符-s,--squeeze-repeats- 将最后一个参数指定的字符去重-t,--truncate-set1- 首先将STRING1的长度截断至和STRING2一样--help- 显示帮助--version- 显示版本
STRING1- 控制字符串列表1STRING2- 控制字符串列表2
#特殊字符
| 转义或表示法 | 含义 |
|---|---|
\NNN | 八进制值为 NNN 的字符（1 到 3 个八进制数字） |
\\ | 反斜杠 |
\a | 可听的 BEL（响铃） |
\b | 退格符 |
\f | 换页符 |
\n | 换行符 |
\r | 回车符 |
\t | 水平制表符 |
\v | 垂直制表符 |
CHAR1-CHAR2 | 从 CHAR1 到 CHAR2 的所有字符（按升序） |
[CHAR*] | 在 ARRAY2 中复制 CHAR，直到 ARRAY1 的长度 |
[CHAR*REPEAT] | 复制 CHAR REPEAT 次，如果 REPEAT 以 0 开头，则为八进制 |
[:alnum:] | 所有字母和数字 |
[:alpha:] | 所有字母 |
[:blank:] | 所有水平空白字符 |
[:cntrl:] | 所有控制字符 |
[:digit:] | 所有数字 |
[:graph:] | 所有可打印字符（不包括空格） |
[:lower:] | 所有小写字母 |
[:print:] | 所有可打印字符（包括空格） |
[:punct:] | 所有标点符号 |
[:space:] | 所有水平或垂直空白字符 |
[:upper:] | 所有大写字母 |
[:xdigit:] | 所有十六进制数字 |
[=CHAR=] | 与 CHAR 等价的所有字符 |
#示例
$ echo "a b c" | tr ' ' '\n' # 将空格替换为换行
a
b
c
$ echo "a b c" | tr 'abc' 'efg' # 将 'abc' 依次替换为 'efg'
e f g
$ echo "a b c" | tr -c 'ac' '-' # 将 'ac' 以外的字符替换为 '-'
a---c-
$ echo "a b c" | tr -d 'a' # 删除 'a'
b c
$ echo "aaa bbb ccc" | tr -d 'b' # 去重 'b'
aaa ccc
#推荐阅读
#手册
TR(1) User Commands TR(1) NAME tr - translate or delete characters SYNOPSIS tr [OPTION]... STRING1 [STRING2] DESCRIPTION Translate, squeeze, and/or delete characters from standard input, writ‐ ing to standard output. STRING1 and STRING2 specify arrays of charac‐ ters ARRAY1 and ARRAY2 that control the action. -c, -C, --complement use the complement of ARRAY1 -d, --delete delete characters in ARRAY1, do not translate -s, --squeeze-repeats replace each sequence of a repeated character that is listed in the last specified ARRAY, with a single occurrence of that char‐ acter -t, --truncate-set1 first truncate ARRAY1 to length of ARRAY2 --help display this help and exit --version output version information and exit ARRAYs are specified as strings of characters. Most represent them‐ selves. Interpreted sequences are: \NNN character with octal value NNN (1 to 3 octal digits) \\ backslash \a audible BEL \b backspace \f form feed \n new line \r return \t horizontal tab \v vertical tab CHAR1-CHAR2 all characters from CHAR1 to CHAR2 in ascending order [CHAR*] in ARRAY2, copies of CHAR until length of ARRAY1 [CHAR*REPEAT] REPEAT copies of CHAR, REPEAT octal if starting with 0 [:alnum:] all letters and digits [:alpha:] all letters [:blank:] all horizontal whitespace [:cntrl:] all control characters [:digit:] all digits [:graph:] all printable characters, not including space [:lower:] all lower case letters [:print:] all printable characters, including space [:punct:] all punctuation characters [:space:] all horizontal or vertical whitespace [:upper:] all upper case letters [:xdigit:] all hexadecimal digits [=CHAR=] all characters which are equivalent to CHAR Translation occurs if -d is not given and both STRING1 and STRING2 ap‐ pear. -t is only significant when translating. ARRAY2 is extended to length of ARRAY1 by repeating its last character as necessary. Excess characters of ARRAY2 are ignored. Character classes expand in unspeci‐ fied order; while translating, [:lower:] and [:upper:] may be used in pairs to specify case conversion. Squeezing occurs after translation or deletion. BUGS Full support is available only for safe single-byte locales, in which every possible input byte represents a single character. The C locale is safe in GNU systems, so you can avoid this issue in the shell by running LC_ALL=C tr instead of plain tr. AUTHOR Written by Jim Meyering. REPORTING BUGS GNU coreutils online help: <https://www.gnu.org/software/coreutils/> Report any translation bugs to <https://translationproject.org/team/> COPYRIGHT Copyright © 2023 Free Software Foundation, Inc. License GPLv3+: GNU GPL version 3 or later <https://gnu.org/licenses/gpl.html>. This is free software: you are free to change and redistribute it. There is NO WARRANTY, to the extent permitted by law. SEE ALSO Full documentation <https://www.gnu.org/software/coreutils/tr> or available locally via: info '(coreutils) tr invocation' GNU coreutils 9.4 April 2024 TR(1)