Use read line to iterate over variables











up vote
3
down vote

favorite












I have the following files:



$ ls *.png | egrep -i "am|pm"
output-0 11.42.30 AM.png
output-0 5.10.12 PM.png
....


I want to remove them but get this error:



$ ls *.png | egrep -i "am|pm" | while read line; do rm "$line"; done
rm: cannot remove ''$'33''[0m'$'33''[01;35moutput-0 11.42.30 AM.png'$'33''[0m': No such file or directory
rm: cannot remove ''$'33''[01;35moutput-0 5.10.12 PM.png'$'33''[0m': No such file or directory
rm: cannot remove ''$'33''[01;35moutput-1 11.42.30 AM.png'$'33''[0m': No such file or directory


What's the problem with my codes?










share|improve this question




















  • 3




    I suspect ls is aliased to ls --color=always instead of ...=auto. Try ls ... to run the actual ls command and not some alias.
    – PerlDuck
    Dec 2 at 10:33






  • 4




    Please also see Why not parse ls (and what do to instead)?
    – Byte Commander
    Dec 2 at 16:03






  • 3




    and Bash pitfalls: for f in $(ls *.mp3) and Why you shouldn't parse the output of ls
    – Byte Commander
    Dec 2 at 16:08















up vote
3
down vote

favorite












I have the following files:



$ ls *.png | egrep -i "am|pm"
output-0 11.42.30 AM.png
output-0 5.10.12 PM.png
....


I want to remove them but get this error:



$ ls *.png | egrep -i "am|pm" | while read line; do rm "$line"; done
rm: cannot remove ''$'33''[0m'$'33''[01;35moutput-0 11.42.30 AM.png'$'33''[0m': No such file or directory
rm: cannot remove ''$'33''[01;35moutput-0 5.10.12 PM.png'$'33''[0m': No such file or directory
rm: cannot remove ''$'33''[01;35moutput-1 11.42.30 AM.png'$'33''[0m': No such file or directory


What's the problem with my codes?










share|improve this question




















  • 3




    I suspect ls is aliased to ls --color=always instead of ...=auto. Try ls ... to run the actual ls command and not some alias.
    – PerlDuck
    Dec 2 at 10:33






  • 4




    Please also see Why not parse ls (and what do to instead)?
    – Byte Commander
    Dec 2 at 16:03






  • 3




    and Bash pitfalls: for f in $(ls *.mp3) and Why you shouldn't parse the output of ls
    – Byte Commander
    Dec 2 at 16:08













up vote
3
down vote

favorite









up vote
3
down vote

favorite











I have the following files:



$ ls *.png | egrep -i "am|pm"
output-0 11.42.30 AM.png
output-0 5.10.12 PM.png
....


I want to remove them but get this error:



$ ls *.png | egrep -i "am|pm" | while read line; do rm "$line"; done
rm: cannot remove ''$'33''[0m'$'33''[01;35moutput-0 11.42.30 AM.png'$'33''[0m': No such file or directory
rm: cannot remove ''$'33''[01;35moutput-0 5.10.12 PM.png'$'33''[0m': No such file or directory
rm: cannot remove ''$'33''[01;35moutput-1 11.42.30 AM.png'$'33''[0m': No such file or directory


What's the problem with my codes?










share|improve this question















I have the following files:



$ ls *.png | egrep -i "am|pm"
output-0 11.42.30 AM.png
output-0 5.10.12 PM.png
....


I want to remove them but get this error:



$ ls *.png | egrep -i "am|pm" | while read line; do rm "$line"; done
rm: cannot remove ''$'33''[0m'$'33''[01;35moutput-0 11.42.30 AM.png'$'33''[0m': No such file or directory
rm: cannot remove ''$'33''[01;35moutput-0 5.10.12 PM.png'$'33''[0m': No such file or directory
rm: cannot remove ''$'33''[01;35moutput-1 11.42.30 AM.png'$'33''[0m': No such file or directory


What's the problem with my codes?







command-line bash ls






share|improve this question















share|improve this question













share|improve this question




share|improve this question








edited Dec 2 at 16:02









Byte Commander

62.5k26169283




62.5k26169283










asked Dec 2 at 10:23









user10726006

303




303








  • 3




    I suspect ls is aliased to ls --color=always instead of ...=auto. Try ls ... to run the actual ls command and not some alias.
    – PerlDuck
    Dec 2 at 10:33






  • 4




    Please also see Why not parse ls (and what do to instead)?
    – Byte Commander
    Dec 2 at 16:03






  • 3




    and Bash pitfalls: for f in $(ls *.mp3) and Why you shouldn't parse the output of ls
    – Byte Commander
    Dec 2 at 16:08














  • 3




    I suspect ls is aliased to ls --color=always instead of ...=auto. Try ls ... to run the actual ls command and not some alias.
    – PerlDuck
    Dec 2 at 10:33






  • 4




    Please also see Why not parse ls (and what do to instead)?
    – Byte Commander
    Dec 2 at 16:03






  • 3




    and Bash pitfalls: for f in $(ls *.mp3) and Why you shouldn't parse the output of ls
    – Byte Commander
    Dec 2 at 16:08








3




3




I suspect ls is aliased to ls --color=always instead of ...=auto. Try ls ... to run the actual ls command and not some alias.
– PerlDuck
Dec 2 at 10:33




I suspect ls is aliased to ls --color=always instead of ...=auto. Try ls ... to run the actual ls command and not some alias.
– PerlDuck
Dec 2 at 10:33




4




4




Please also see Why not parse ls (and what do to instead)?
– Byte Commander
Dec 2 at 16:03




Please also see Why not parse ls (and what do to instead)?
– Byte Commander
Dec 2 at 16:03




3




3




and Bash pitfalls: for f in $(ls *.mp3) and Why you shouldn't parse the output of ls
– Byte Commander
Dec 2 at 16:08




and Bash pitfalls: for f in $(ls *.mp3) and Why you shouldn't parse the output of ls
– Byte Commander
Dec 2 at 16:08










2 Answers
2






active

oldest

votes

















up vote
9
down vote



accepted










ls is risky in scripts and command lines. One problem is what is described in a comment by @PerlDuck, ANSI escape sequences for colour output. I would recommend another approach with find





  • Create test files



    touch 'output-0 11.42.30 AM.png' 'output-0 5.10.12 PM.png' asdf.png



  • Check that the findcommand line finds the files that you expect it to find



    find . -type f -iname "*[ap]m*.png"


    and do it



    find . -type f -iname "*[ap]m*.png" -delete


    If you don't want to search into subdirectories, add -maxdepth 1



    find . -maxdepth 1 -type f -iname "*[ap]m*.png" -delete



  • Check the result



    ls


    Files with am, pm, AM, PM in the name should be deleted but asdf.png is not deleted.








share|improve this answer






























    up vote
    6
    down vote













    If you really want to use a while read loop in that way, then use a shell glob and printf with null delimiters e.g.



    printf '%s' *.png | grep -zEi 'am|pm' | while IFS= read -r -d '' line; do echo "$line"; done


    However, there are several ways to get bash to expand to a list of the files to be deleted directly - without the need to pipe to grep and while:





    1. using simple shell globs



      rm -- *[ap]m.png *[AP]M.png


      or - if you don't mind matching a .PNG extension as well - making use of the nocaseglob option



      shopt -s nocaseglob
      rm -- *[ap]m.png



    2. using extended globs



      shopt -s extglob
      rm -- *@(AM|PM).png *@(am|pm).png



    or



        shopt -s extglob nocaseglob
    rm -- *@(am|pm).png


    The -- marks the end of options, just in case there are filenames that begin with a hyphen - you can use a pattern with an explicit directory prefix like ./*(am|pm) instead if you prefer.



    Add the -i or -I option if you want to review the file names interactively before deletion.






    share|improve this answer























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      2 Answers
      2






      active

      oldest

      votes








      2 Answers
      2






      active

      oldest

      votes









      active

      oldest

      votes






      active

      oldest

      votes








      up vote
      9
      down vote



      accepted










      ls is risky in scripts and command lines. One problem is what is described in a comment by @PerlDuck, ANSI escape sequences for colour output. I would recommend another approach with find





      • Create test files



        touch 'output-0 11.42.30 AM.png' 'output-0 5.10.12 PM.png' asdf.png



      • Check that the findcommand line finds the files that you expect it to find



        find . -type f -iname "*[ap]m*.png"


        and do it



        find . -type f -iname "*[ap]m*.png" -delete


        If you don't want to search into subdirectories, add -maxdepth 1



        find . -maxdepth 1 -type f -iname "*[ap]m*.png" -delete



      • Check the result



        ls


        Files with am, pm, AM, PM in the name should be deleted but asdf.png is not deleted.








      share|improve this answer



























        up vote
        9
        down vote



        accepted










        ls is risky in scripts and command lines. One problem is what is described in a comment by @PerlDuck, ANSI escape sequences for colour output. I would recommend another approach with find





        • Create test files



          touch 'output-0 11.42.30 AM.png' 'output-0 5.10.12 PM.png' asdf.png



        • Check that the findcommand line finds the files that you expect it to find



          find . -type f -iname "*[ap]m*.png"


          and do it



          find . -type f -iname "*[ap]m*.png" -delete


          If you don't want to search into subdirectories, add -maxdepth 1



          find . -maxdepth 1 -type f -iname "*[ap]m*.png" -delete



        • Check the result



          ls


          Files with am, pm, AM, PM in the name should be deleted but asdf.png is not deleted.








        share|improve this answer

























          up vote
          9
          down vote



          accepted







          up vote
          9
          down vote



          accepted






          ls is risky in scripts and command lines. One problem is what is described in a comment by @PerlDuck, ANSI escape sequences for colour output. I would recommend another approach with find





          • Create test files



            touch 'output-0 11.42.30 AM.png' 'output-0 5.10.12 PM.png' asdf.png



          • Check that the findcommand line finds the files that you expect it to find



            find . -type f -iname "*[ap]m*.png"


            and do it



            find . -type f -iname "*[ap]m*.png" -delete


            If you don't want to search into subdirectories, add -maxdepth 1



            find . -maxdepth 1 -type f -iname "*[ap]m*.png" -delete



          • Check the result



            ls


            Files with am, pm, AM, PM in the name should be deleted but asdf.png is not deleted.








          share|improve this answer














          ls is risky in scripts and command lines. One problem is what is described in a comment by @PerlDuck, ANSI escape sequences for colour output. I would recommend another approach with find





          • Create test files



            touch 'output-0 11.42.30 AM.png' 'output-0 5.10.12 PM.png' asdf.png



          • Check that the findcommand line finds the files that you expect it to find



            find . -type f -iname "*[ap]m*.png"


            and do it



            find . -type f -iname "*[ap]m*.png" -delete


            If you don't want to search into subdirectories, add -maxdepth 1



            find . -maxdepth 1 -type f -iname "*[ap]m*.png" -delete



          • Check the result



            ls


            Files with am, pm, AM, PM in the name should be deleted but asdf.png is not deleted.









          share|improve this answer














          share|improve this answer



          share|improve this answer








          edited Dec 2 at 15:51

























          answered Dec 2 at 10:58









          sudodus

          22.1k32871




          22.1k32871
























              up vote
              6
              down vote













              If you really want to use a while read loop in that way, then use a shell glob and printf with null delimiters e.g.



              printf '%s' *.png | grep -zEi 'am|pm' | while IFS= read -r -d '' line; do echo "$line"; done


              However, there are several ways to get bash to expand to a list of the files to be deleted directly - without the need to pipe to grep and while:





              1. using simple shell globs



                rm -- *[ap]m.png *[AP]M.png


                or - if you don't mind matching a .PNG extension as well - making use of the nocaseglob option



                shopt -s nocaseglob
                rm -- *[ap]m.png



              2. using extended globs



                shopt -s extglob
                rm -- *@(AM|PM).png *@(am|pm).png



              or



                  shopt -s extglob nocaseglob
              rm -- *@(am|pm).png


              The -- marks the end of options, just in case there are filenames that begin with a hyphen - you can use a pattern with an explicit directory prefix like ./*(am|pm) instead if you prefer.



              Add the -i or -I option if you want to review the file names interactively before deletion.






              share|improve this answer



























                up vote
                6
                down vote













                If you really want to use a while read loop in that way, then use a shell glob and printf with null delimiters e.g.



                printf '%s' *.png | grep -zEi 'am|pm' | while IFS= read -r -d '' line; do echo "$line"; done


                However, there are several ways to get bash to expand to a list of the files to be deleted directly - without the need to pipe to grep and while:





                1. using simple shell globs



                  rm -- *[ap]m.png *[AP]M.png


                  or - if you don't mind matching a .PNG extension as well - making use of the nocaseglob option



                  shopt -s nocaseglob
                  rm -- *[ap]m.png



                2. using extended globs



                  shopt -s extglob
                  rm -- *@(AM|PM).png *@(am|pm).png



                or



                    shopt -s extglob nocaseglob
                rm -- *@(am|pm).png


                The -- marks the end of options, just in case there are filenames that begin with a hyphen - you can use a pattern with an explicit directory prefix like ./*(am|pm) instead if you prefer.



                Add the -i or -I option if you want to review the file names interactively before deletion.






                share|improve this answer

























                  up vote
                  6
                  down vote










                  up vote
                  6
                  down vote









                  If you really want to use a while read loop in that way, then use a shell glob and printf with null delimiters e.g.



                  printf '%s' *.png | grep -zEi 'am|pm' | while IFS= read -r -d '' line; do echo "$line"; done


                  However, there are several ways to get bash to expand to a list of the files to be deleted directly - without the need to pipe to grep and while:





                  1. using simple shell globs



                    rm -- *[ap]m.png *[AP]M.png


                    or - if you don't mind matching a .PNG extension as well - making use of the nocaseglob option



                    shopt -s nocaseglob
                    rm -- *[ap]m.png



                  2. using extended globs



                    shopt -s extglob
                    rm -- *@(AM|PM).png *@(am|pm).png



                  or



                      shopt -s extglob nocaseglob
                  rm -- *@(am|pm).png


                  The -- marks the end of options, just in case there are filenames that begin with a hyphen - you can use a pattern with an explicit directory prefix like ./*(am|pm) instead if you prefer.



                  Add the -i or -I option if you want to review the file names interactively before deletion.






                  share|improve this answer














                  If you really want to use a while read loop in that way, then use a shell glob and printf with null delimiters e.g.



                  printf '%s' *.png | grep -zEi 'am|pm' | while IFS= read -r -d '' line; do echo "$line"; done


                  However, there are several ways to get bash to expand to a list of the files to be deleted directly - without the need to pipe to grep and while:





                  1. using simple shell globs



                    rm -- *[ap]m.png *[AP]M.png


                    or - if you don't mind matching a .PNG extension as well - making use of the nocaseglob option



                    shopt -s nocaseglob
                    rm -- *[ap]m.png



                  2. using extended globs



                    shopt -s extglob
                    rm -- *@(AM|PM).png *@(am|pm).png



                  or



                      shopt -s extglob nocaseglob
                  rm -- *@(am|pm).png


                  The -- marks the end of options, just in case there are filenames that begin with a hyphen - you can use a pattern with an explicit directory prefix like ./*(am|pm) instead if you prefer.



                  Add the -i or -I option if you want to review the file names interactively before deletion.







                  share|improve this answer














                  share|improve this answer



                  share|improve this answer








                  edited Dec 2 at 16:22

























                  answered Dec 2 at 13:27









                  steeldriver

                  65.1k11104176




                  65.1k11104176






























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