Fastest way to delete files with 0 size












1














I am in search of the fastest possible way to delete files with 0 size using bash.



I have hundreds of thousands of files with 0 size being generated (alongside valuable output) into a single output directory from a grep command run with GNU parallel. When grep finds a match the output file contains information. When grep does not find a match the output file is empty.



parallel -j $numcores "grepfunction {} > output_{}.fastq" ::: "${input_array[@]}"


I am using the following to remove the empty files but I would like to find a faster option. In searching most of the solutions I have found use similar find based commands that work at similar speeds.



find results2/ -size 0 -delete


As suggested in the comment i have also tried the following



find ./results2 -size 0 -print0 |xargs -0 rm --


It is qualitatively slow but I will benchmark and report back.



Any suggestions are much appreciated.






linux bash delete-file







share|improve this question
























  • Maybe using find to get the files and xargs to perform the rm in parallel. Try and benchmark.
    – Poshi
    Nov 20 '18 at 20:15






  • 5




    would be overall way more efficient if you modified your parallel thing to not generate files if there is no information.
    – Mat
    Nov 20 '18 at 20:19






  • 1




    I doubt there will be anything faster than find results2/ -size 0 -delete, as that is one process generating a number of system calls. find with xargs is at least three processes (find, xargs, and one or more calls to rm), and rm is going to do the same thing find ... -delete does: make some number of system calls to delete each file individually.
    – chepner
    Nov 20 '18 at 20:24










  • I think you'll find that find ... | parallel -X rm is quicker than find ... | xargs rm ... because parallel will, respecting ARGMAX, give as many files as possible to each invocation of rm.... though @chepner's answers are normally roughly 376,892 times better than mine :-)
    – Mark Setchell
    Nov 20 '18 at 20:25








  • 1




    I've never had to use parallel, so I'm not exactly sure how it would work, but if your grep_function returns a non-zero status when not finding anything, you could do something like "grep_function {} >output_{}.fastq || rm -f output_{}.fastq" to remove the empty files within your parallel invocation.
    – Lewis M
    Nov 20 '18 at 21:21
















1














I am in search of the fastest possible way to delete files with 0 size using bash.



I have hundreds of thousands of files with 0 size being generated (alongside valuable output) into a single output directory from a grep command run with GNU parallel. When grep finds a match the output file contains information. When grep does not find a match the output file is empty.



parallel -j $numcores "grepfunction {} > output_{}.fastq" ::: "${input_array[@]}"


I am using the following to remove the empty files but I would like to find a faster option. In searching most of the solutions I have found use similar find based commands that work at similar speeds.



find results2/ -size 0 -delete


As suggested in the comment i have also tried the following



find ./results2 -size 0 -print0 |xargs -0 rm --


It is qualitatively slow but I will benchmark and report back.



Any suggestions are much appreciated.






linux bash delete-file







share|improve this question
























  • Maybe using find to get the files and xargs to perform the rm in parallel. Try and benchmark.
    – Poshi
    Nov 20 '18 at 20:15






  • 5




    would be overall way more efficient if you modified your parallel thing to not generate files if there is no information.
    – Mat
    Nov 20 '18 at 20:19






  • 1




    I doubt there will be anything faster than find results2/ -size 0 -delete, as that is one process generating a number of system calls. find with xargs is at least three processes (find, xargs, and one or more calls to rm), and rm is going to do the same thing find ... -delete does: make some number of system calls to delete each file individually.
    – chepner
    Nov 20 '18 at 20:24










  • I think you'll find that find ... | parallel -X rm is quicker than find ... | xargs rm ... because parallel will, respecting ARGMAX, give as many files as possible to each invocation of rm.... though @chepner's answers are normally roughly 376,892 times better than mine :-)
    – Mark Setchell
    Nov 20 '18 at 20:25








  • 1




    I've never had to use parallel, so I'm not exactly sure how it would work, but if your grep_function returns a non-zero status when not finding anything, you could do something like "grep_function {} >output_{}.fastq || rm -f output_{}.fastq" to remove the empty files within your parallel invocation.
    – Lewis M
    Nov 20 '18 at 21:21














1












1








1







I am in search of the fastest possible way to delete files with 0 size using bash.



I have hundreds of thousands of files with 0 size being generated (alongside valuable output) into a single output directory from a grep command run with GNU parallel. When grep finds a match the output file contains information. When grep does not find a match the output file is empty.



parallel -j $numcores "grepfunction {} > output_{}.fastq" ::: "${input_array[@]}"


I am using the following to remove the empty files but I would like to find a faster option. In searching most of the solutions I have found use similar find based commands that work at similar speeds.



find results2/ -size 0 -delete


As suggested in the comment i have also tried the following



find ./results2 -size 0 -print0 |xargs -0 rm --


It is qualitatively slow but I will benchmark and report back.



Any suggestions are much appreciated.






linux bash delete-file







share|improve this question















I am in search of the fastest possible way to delete files with 0 size using bash.



I have hundreds of thousands of files with 0 size being generated (alongside valuable output) into a single output directory from a grep command run with GNU parallel. When grep finds a match the output file contains information. When grep does not find a match the output file is empty.



parallel -j $numcores "grepfunction {} > output_{}.fastq" ::: "${input_array[@]}"


I am using the following to remove the empty files but I would like to find a faster option. In searching most of the solutions I have found use similar find based commands that work at similar speeds.



find results2/ -size 0 -delete


As suggested in the comment i have also tried the following



find ./results2 -size 0 -print0 |xargs -0 rm --


It is qualitatively slow but I will benchmark and report back.



Any suggestions are much appreciated.






linux bash delete-file




linux bash delete-file






share|improve this question















share|improve this question













share|improve this question




share|improve this question








edited Nov 20 '18 at 20:16

























asked Nov 20 '18 at 20:12









Paul

256112




256112












  • Maybe using find to get the files and xargs to perform the rm in parallel. Try and benchmark.
    – Poshi
    Nov 20 '18 at 20:15






  • 5




    would be overall way more efficient if you modified your parallel thing to not generate files if there is no information.
    – Mat
    Nov 20 '18 at 20:19






  • 1




    I doubt there will be anything faster than find results2/ -size 0 -delete, as that is one process generating a number of system calls. find with xargs is at least three processes (find, xargs, and one or more calls to rm), and rm is going to do the same thing find ... -delete does: make some number of system calls to delete each file individually.
    – chepner
    Nov 20 '18 at 20:24










  • I think you'll find that find ... | parallel -X rm is quicker than find ... | xargs rm ... because parallel will, respecting ARGMAX, give as many files as possible to each invocation of rm.... though @chepner's answers are normally roughly 376,892 times better than mine :-)
    – Mark Setchell
    Nov 20 '18 at 20:25








  • 1




    I've never had to use parallel, so I'm not exactly sure how it would work, but if your grep_function returns a non-zero status when not finding anything, you could do something like "grep_function {} >output_{}.fastq || rm -f output_{}.fastq" to remove the empty files within your parallel invocation.
    – Lewis M
    Nov 20 '18 at 21:21


















  • Maybe using find to get the files and xargs to perform the rm in parallel. Try and benchmark.
    – Poshi
    Nov 20 '18 at 20:15






  • 5




    would be overall way more efficient if you modified your parallel thing to not generate files if there is no information.
    – Mat
    Nov 20 '18 at 20:19






  • 1




    I doubt there will be anything faster than find results2/ -size 0 -delete, as that is one process generating a number of system calls. find with xargs is at least three processes (find, xargs, and one or more calls to rm), and rm is going to do the same thing find ... -delete does: make some number of system calls to delete each file individually.
    – chepner
    Nov 20 '18 at 20:24










  • I think you'll find that find ... | parallel -X rm is quicker than find ... | xargs rm ... because parallel will, respecting ARGMAX, give as many files as possible to each invocation of rm.... though @chepner's answers are normally roughly 376,892 times better than mine :-)
    – Mark Setchell
    Nov 20 '18 at 20:25








  • 1




    I've never had to use parallel, so I'm not exactly sure how it would work, but if your grep_function returns a non-zero status when not finding anything, you could do something like "grep_function {} >output_{}.fastq || rm -f output_{}.fastq" to remove the empty files within your parallel invocation.
    – Lewis M
    Nov 20 '18 at 21:21
















Maybe using find to get the files and xargs to perform the rm in parallel. Try and benchmark.
– Poshi
Nov 20 '18 at 20:15




Maybe using find to get the files and xargs to perform the rm in parallel. Try and benchmark.
– Poshi
Nov 20 '18 at 20:15




5




5




would be overall way more efficient if you modified your parallel thing to not generate files if there is no information.
– Mat
Nov 20 '18 at 20:19




would be overall way more efficient if you modified your parallel thing to not generate files if there is no information.
– Mat
Nov 20 '18 at 20:19




1




1




I doubt there will be anything faster than find results2/ -size 0 -delete, as that is one process generating a number of system calls. find with xargs is at least three processes (find, xargs, and one or more calls to rm), and rm is going to do the same thing find ... -delete does: make some number of system calls to delete each file individually.
– chepner
Nov 20 '18 at 20:24




I doubt there will be anything faster than find results2/ -size 0 -delete, as that is one process generating a number of system calls. find with xargs is at least three processes (find, xargs, and one or more calls to rm), and rm is going to do the same thing find ... -delete does: make some number of system calls to delete each file individually.
– chepner
Nov 20 '18 at 20:24












I think you'll find that find ... | parallel -X rm is quicker than find ... | xargs rm ... because parallel will, respecting ARGMAX, give as many files as possible to each invocation of rm.... though @chepner's answers are normally roughly 376,892 times better than mine :-)
– Mark Setchell
Nov 20 '18 at 20:25






I think you'll find that find ... | parallel -X rm is quicker than find ... | xargs rm ... because parallel will, respecting ARGMAX, give as many files as possible to each invocation of rm.... though @chepner's answers are normally roughly 376,892 times better than mine :-)
– Mark Setchell
Nov 20 '18 at 20:25






1




1




I've never had to use parallel, so I'm not exactly sure how it would work, but if your grep_function returns a non-zero status when not finding anything, you could do something like "grep_function {} >output_{}.fastq || rm -f output_{}.fastq" to remove the empty files within your parallel invocation.
– Lewis M
Nov 20 '18 at 21:21




I've never had to use parallel, so I'm not exactly sure how it would work, but if your grep_function returns a non-zero status when not finding anything, you could do something like "grep_function {} >output_{}.fastq || rm -f output_{}.fastq" to remove the empty files within your parallel invocation.
– Lewis M
Nov 20 '18 at 21:21












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(This should be a comment, but is too hard to read as a comment).



If you are going to run the jobs again you could make it part of the generating of the file:



parallel -j $numcores "grepfunction {} > output_{}.fastq ||

  rm output_{}.fastq" ::: "${input_array[@]}"


I assume the grep function returns true if match (like grep does).






share|improve this answer





















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    (This should be a comment, but is too hard to read as a comment).



    If you are going to run the jobs again you could make it part of the generating of the file:



    parallel -j $numcores "grepfunction {} > output_{}.fastq ||
    
  rm output_{}.fastq" ::: "${input_array[@]}"


    I assume the grep function returns true if match (like grep does).






    share|improve this answer


























      0














      (This should be a comment, but is too hard to read as a comment).



      If you are going to run the jobs again you could make it part of the generating of the file:



      parallel -j $numcores "grepfunction {} > output_{}.fastq ||
      
  rm output_{}.fastq" ::: "${input_array[@]}"


      I assume the grep function returns true if match (like grep does).






      share|improve this answer
























        0












        0








        0






        (This should be a comment, but is too hard to read as a comment).



        If you are going to run the jobs again you could make it part of the generating of the file:



        parallel -j $numcores "grepfunction {} > output_{}.fastq ||
        
  rm output_{}.fastq" ::: "${input_array[@]}"


        I assume the grep function returns true if match (like grep does).






        share|improve this answer












        (This should be a comment, but is too hard to read as a comment).



        If you are going to run the jobs again you could make it part of the generating of the file:



        parallel -j $numcores "grepfunction {} > output_{}.fastq ||
        
  rm output_{}.fastq" ::: "${input_array[@]}"


        I assume the grep function returns true if match (like grep does).







        share|improve this answer












        share|improve this answer



        share|improve this answer










        answered Nov 21 '18 at 8:15









        Ole Tange

        19k35566




        19k35566






























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