How to detect line break and non-space character in bash case logic?

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I'm writing a bash script and using the case logic to detect if my $message has non-space character, but I also want to detect non-line-break as well. Sometimes my script has the $message variable equal to a line-break and its returning true sometimes.



How do I combine a non-space and non-line-break condition?




Like this? [! !n]




This is what I have so far:



 7 case $message in
8 *[! ]*) # contains non-space
9 messagex='``` '"$message"' ```' ;;
10 *) # contains nothing or only spaces
11 messagex=
12 esac









share|improve this question


























    0















    I'm writing a bash script and using the case logic to detect if my $message has non-space character, but I also want to detect non-line-break as well. Sometimes my script has the $message variable equal to a line-break and its returning true sometimes.



    How do I combine a non-space and non-line-break condition?




    Like this? [! !n]




    This is what I have so far:



     7 case $message in
    8 *[! ]*) # contains non-space
    9 messagex='``` '"$message"' ```' ;;
    10 *) # contains nothing or only spaces
    11 messagex=
    12 esac









    share|improve this question
























      0












      0








      0








      I'm writing a bash script and using the case logic to detect if my $message has non-space character, but I also want to detect non-line-break as well. Sometimes my script has the $message variable equal to a line-break and its returning true sometimes.



      How do I combine a non-space and non-line-break condition?




      Like this? [! !n]




      This is what I have so far:



       7 case $message in
      8 *[! ]*) # contains non-space
      9 messagex='``` '"$message"' ```' ;;
      10 *) # contains nothing or only spaces
      11 messagex=
      12 esac









      share|improve this question














      I'm writing a bash script and using the case logic to detect if my $message has non-space character, but I also want to detect non-line-break as well. Sometimes my script has the $message variable equal to a line-break and its returning true sometimes.



      How do I combine a non-space and non-line-break condition?




      Like this? [! !n]




      This is what I have so far:



       7 case $message in
      8 *[! ]*) # contains non-space
      9 messagex='``` '"$message"' ```' ;;
      10 *) # contains nothing or only spaces
      11 messagex=
      12 esac






      bash shell-script






      share|improve this question













      share|improve this question











      share|improve this question




      share|improve this question










      asked Mar 5 at 20:41









      Patoshi パトシPatoshi パトシ

      56341322




      56341322




















          1 Answer
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          case $message in
          (*[!'
          ']*) : contains characters other space and newline
          esac


          Or:



          case $message in
          (*[!"$(printf 'n ')"]*) : contains characters other space and newline
          esac


          Or using ksh93-style $'...' special quotes (not in sh):



          case $message in
          (*[!$' n']*) : contains characters other space and newline
          esac


          Or you could use the [:space:] POSIX character class which matches any whitespace including TAB, SPC, CR, NL...



          case $message in
          (*[![:space:]]*) : contains non-whitespace characters
          esac





          share|improve this answer























          • mine doesn't have the semi-colon. do I need that after ) :

            – Patoshi パトシ
            Mar 6 at 16:14











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          1 Answer
          1






          active

          oldest

          votes








          1 Answer
          1






          active

          oldest

          votes









          active

          oldest

          votes






          active

          oldest

          votes









          3














          case $message in
          (*[!'
          ']*) : contains characters other space and newline
          esac


          Or:



          case $message in
          (*[!"$(printf 'n ')"]*) : contains characters other space and newline
          esac


          Or using ksh93-style $'...' special quotes (not in sh):



          case $message in
          (*[!$' n']*) : contains characters other space and newline
          esac


          Or you could use the [:space:] POSIX character class which matches any whitespace including TAB, SPC, CR, NL...



          case $message in
          (*[![:space:]]*) : contains non-whitespace characters
          esac





          share|improve this answer























          • mine doesn't have the semi-colon. do I need that after ) :

            – Patoshi パトシ
            Mar 6 at 16:14















          3














          case $message in
          (*[!'
          ']*) : contains characters other space and newline
          esac


          Or:



          case $message in
          (*[!"$(printf 'n ')"]*) : contains characters other space and newline
          esac


          Or using ksh93-style $'...' special quotes (not in sh):



          case $message in
          (*[!$' n']*) : contains characters other space and newline
          esac


          Or you could use the [:space:] POSIX character class which matches any whitespace including TAB, SPC, CR, NL...



          case $message in
          (*[![:space:]]*) : contains non-whitespace characters
          esac





          share|improve this answer























          • mine doesn't have the semi-colon. do I need that after ) :

            – Patoshi パトシ
            Mar 6 at 16:14













          3












          3








          3







          case $message in
          (*[!'
          ']*) : contains characters other space and newline
          esac


          Or:



          case $message in
          (*[!"$(printf 'n ')"]*) : contains characters other space and newline
          esac


          Or using ksh93-style $'...' special quotes (not in sh):



          case $message in
          (*[!$' n']*) : contains characters other space and newline
          esac


          Or you could use the [:space:] POSIX character class which matches any whitespace including TAB, SPC, CR, NL...



          case $message in
          (*[![:space:]]*) : contains non-whitespace characters
          esac





          share|improve this answer













          case $message in
          (*[!'
          ']*) : contains characters other space and newline
          esac


          Or:



          case $message in
          (*[!"$(printf 'n ')"]*) : contains characters other space and newline
          esac


          Or using ksh93-style $'...' special quotes (not in sh):



          case $message in
          (*[!$' n']*) : contains characters other space and newline
          esac


          Or you could use the [:space:] POSIX character class which matches any whitespace including TAB, SPC, CR, NL...



          case $message in
          (*[![:space:]]*) : contains non-whitespace characters
          esac






          share|improve this answer












          share|improve this answer



          share|improve this answer










          answered Mar 5 at 22:08









          Stéphane ChazelasStéphane Chazelas

          312k57592948




          312k57592948












          • mine doesn't have the semi-colon. do I need that after ) :

            – Patoshi パトシ
            Mar 6 at 16:14

















          • mine doesn't have the semi-colon. do I need that after ) :

            – Patoshi パトシ
            Mar 6 at 16:14
















          mine doesn't have the semi-colon. do I need that after ) :

          – Patoshi パトシ
          Mar 6 at 16:14





          mine doesn't have the semi-colon. do I need that after ) :

          – Patoshi パトシ
          Mar 6 at 16:14

















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