tr -d [=,=] 是做什么的?
What does tr -d [=,=] do?
我有一个代码示例,似乎在某些文本处理的末尾附加了一段额外的格式:
tr -d [=,=]
我不知道这有什么用,tr
的手册页帮不上什么忙。对此有何见解?
它只会删除 ==
之间的逗号。检查下面的输出。
%_Host@User> echo "1==,==2==,==3=,=4=,=5" | tr -d [=,=]
1====2====3==4==5
%_Host@User>
谢谢。
来自 man tr
页面,
[=equiv=]
Equivalence classes
The syntax [=C=]
expands to all of the characters that are equivalent to C
, in no particular order. Equivalence classes are a relatively recent invention intended to support non-English alphabets. But there seems to be no standard way to define them or determine their contents. Therefore, they are not fully implemented in GNU tr
; each character's equivalence class consists only of that character, which is of no particular use.
来自 POSIX tr
页面的示例
此示例使用等价 class 来识别文件 1 中基本字符 'e'
的重音变体,这些变体从 diacritical marks (WikiLink) 中剥离并写入文件 2。
tr "[=e=]" "[e*]" <file1 >file2
即如果在 file1 中,如果 e
表示为重音符号(é
或 è
),它们将被视为正常 e
我有一个代码示例,似乎在某些文本处理的末尾附加了一段额外的格式:
tr -d [=,=]
我不知道这有什么用,tr
的手册页帮不上什么忙。对此有何见解?
它只会删除 ==
之间的逗号。检查下面的输出。
%_Host@User> echo "1==,==2==,==3=,=4=,=5" | tr -d [=,=]
1====2====3==4==5
%_Host@User>
谢谢。
来自 man tr
页面,
[=equiv=]
Equivalence classes
The syntax
[=C=]
expands to all of the characters that are equivalent toC
, in no particular order. Equivalence classes are a relatively recent invention intended to support non-English alphabets. But there seems to be no standard way to define them or determine their contents. Therefore, they are not fully implemented inGNU tr
; each character's equivalence class consists only of that character, which is of no particular use.
来自 POSIX tr
页面的示例
此示例使用等价 class 来识别文件 1 中基本字符 'e'
的重音变体,这些变体从 diacritical marks (WikiLink) 中剥离并写入文件 2。
tr "[=e=]" "[e*]" <file1 >file2
即如果在 file1 中,如果 e
表示为重音符号(é
或 è
),它们将被视为正常 e