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$'s/\r$//' 정규식은 무엇을 합니까?

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$'s/\r$//' 정규식은 무엇을 합니까?

Todd Schneider는 그의 작업에서 다음 명령을 사용했습니다.뉴욕시 택시 데이터 분석PostresSQL용 CSV 파일을 준비합니다.

sed $'s/\r$//' $filename | sed '/^$/d' | ...

두 번째 sed 명령은 빈 줄을 제거합니다. 첫 번째는 무엇을 합니까?

답변1

에 따르면 man bash:

  Words of the form $'string' are treated specially.  The word expands to
   string,  with backslash-escaped characters replaced as specified by the
   ANSI C standard.  Backslash escape sequences, if present,  are  decoded
   as follows:                                      
          \a     alert (bell)                       
          \b     backspace                          
          \e                                        
          \E     an escape character                
          \f     form feed                          
          \n     new line                           
          \r     carriage return                    
          \t     horizontal tab                     
          \v     vertical tab                       
          \\     backslash                          
          \'     single quote                       
          \"     double quote                       
          \?     question mark                      
          \nnn   the  eight-bit  character  whose value is the octal value
                 nnn (one to three digits)          
          \xHH   the eight-bit character whose value  is  the  hexadecimal
                 value HH (one or two hex digits)   
          \uHHHH the  Unicode (ISO/IEC 10646) character whose value is the
                 hexadecimal value HHHH (one to four hex digits)
          \UHHHHHHHH                                
                 the Unicode (ISO/IEC 10646) character whose value is  the
                 hexadecimal value HHHHHHHH (one to eight hex digits)
          \cx    a control-x character              
  The  expanded  result  is  single-quoted, as if the dollar sign had not
   been present.

따라서 $'s/\r$//'줄 끝에서 ASCII를 제거하십시오. CR이는 Windows 줄 종결자를 UNIX 줄 종결자로 변환하는 조잡한 방법입니다.

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