Iterating over files in Bash and obtaining the index and the counts












2














The proper way to iterate over files in a directory in Bash is using "for loop" and glob as following:



for f in *.jpg; do
echo "- Processing file: $f"
done


But how can I retrieve the total count of the files and the current index of the loop interaction? I need the total count, not the cumulative count to show the progress.










share|improve this question





























    2














    The proper way to iterate over files in a directory in Bash is using "for loop" and glob as following:



    for f in *.jpg; do
    echo "- Processing file: $f"
    done


    But how can I retrieve the total count of the files and the current index of the loop interaction? I need the total count, not the cumulative count to show the progress.










    share|improve this question



























      2












      2








      2







      The proper way to iterate over files in a directory in Bash is using "for loop" and glob as following:



      for f in *.jpg; do
      echo "- Processing file: $f"
      done


      But how can I retrieve the total count of the files and the current index of the loop interaction? I need the total count, not the cumulative count to show the progress.










      share|improve this question















      The proper way to iterate over files in a directory in Bash is using "for loop" and glob as following:



      for f in *.jpg; do
      echo "- Processing file: $f"
      done


      But how can I retrieve the total count of the files and the current index of the loop interaction? I need the total count, not the cumulative count to show the progress.







      shell-script






      share|improve this question















      share|improve this question













      share|improve this question




      share|improve this question








      edited 5 hours ago

























      asked 5 hours ago









      bman

      13019




      13019






















          1 Answer
          1






          active

          oldest

          votes


















          4














          I would store the list of files in an array, so that you don't have to read the file system twice, increasing performance and reducing potential race conditions. Then use another variable as the index.



          files=(*.jpg)
          total=${#files[@]}
          i=0
          for f in "${files[@]}"; do
          i=$(( i + 1 ))
          echo index $i
          echo total $total
          echo "- Processing file: $f"
          done


          Explanation





          • files=(*.jpg): store the glob into the array $files


          • total=${#files[@]}: read the total into $total


          • i=0: initialise $i to 0.


          • i=$(( i + 1 )): add 1 to $i each loop


          This presumes that the "first" loop is 1. Depending on your opinion, you might want to start at 0 instead.






          share|improve this answer























          • I need to know the count while the for loop is running to show the progress, not at the end.
            – bman
            5 hours ago










          • @bman I'm not sure what you mean. This will display the count during each loop, not at the end.
            – Sparhawk
            5 hours ago










          • It displays the index, not the total count of files. I think I should use something like this for obtaining the count of files: ls -1q *.jpg | wc -l
            – bman
            5 hours ago










          • @bman Ah got it. that might work generally, but (as you suggest in your question), parsing ls is not great. Give me a minute and I'll edit.
            – Sparhawk
            5 hours ago










          • @bman Okay done.
            – Sparhawk
            4 hours ago











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          1 Answer
          1






          active

          oldest

          votes








          1 Answer
          1






          active

          oldest

          votes









          active

          oldest

          votes






          active

          oldest

          votes









          4














          I would store the list of files in an array, so that you don't have to read the file system twice, increasing performance and reducing potential race conditions. Then use another variable as the index.



          files=(*.jpg)
          total=${#files[@]}
          i=0
          for f in "${files[@]}"; do
          i=$(( i + 1 ))
          echo index $i
          echo total $total
          echo "- Processing file: $f"
          done


          Explanation





          • files=(*.jpg): store the glob into the array $files


          • total=${#files[@]}: read the total into $total


          • i=0: initialise $i to 0.


          • i=$(( i + 1 )): add 1 to $i each loop


          This presumes that the "first" loop is 1. Depending on your opinion, you might want to start at 0 instead.






          share|improve this answer























          • I need to know the count while the for loop is running to show the progress, not at the end.
            – bman
            5 hours ago










          • @bman I'm not sure what you mean. This will display the count during each loop, not at the end.
            – Sparhawk
            5 hours ago










          • It displays the index, not the total count of files. I think I should use something like this for obtaining the count of files: ls -1q *.jpg | wc -l
            – bman
            5 hours ago










          • @bman Ah got it. that might work generally, but (as you suggest in your question), parsing ls is not great. Give me a minute and I'll edit.
            – Sparhawk
            5 hours ago










          • @bman Okay done.
            – Sparhawk
            4 hours ago
















          4














          I would store the list of files in an array, so that you don't have to read the file system twice, increasing performance and reducing potential race conditions. Then use another variable as the index.



          files=(*.jpg)
          total=${#files[@]}
          i=0
          for f in "${files[@]}"; do
          i=$(( i + 1 ))
          echo index $i
          echo total $total
          echo "- Processing file: $f"
          done


          Explanation





          • files=(*.jpg): store the glob into the array $files


          • total=${#files[@]}: read the total into $total


          • i=0: initialise $i to 0.


          • i=$(( i + 1 )): add 1 to $i each loop


          This presumes that the "first" loop is 1. Depending on your opinion, you might want to start at 0 instead.






          share|improve this answer























          • I need to know the count while the for loop is running to show the progress, not at the end.
            – bman
            5 hours ago










          • @bman I'm not sure what you mean. This will display the count during each loop, not at the end.
            – Sparhawk
            5 hours ago










          • It displays the index, not the total count of files. I think I should use something like this for obtaining the count of files: ls -1q *.jpg | wc -l
            – bman
            5 hours ago










          • @bman Ah got it. that might work generally, but (as you suggest in your question), parsing ls is not great. Give me a minute and I'll edit.
            – Sparhawk
            5 hours ago










          • @bman Okay done.
            – Sparhawk
            4 hours ago














          4












          4








          4






          I would store the list of files in an array, so that you don't have to read the file system twice, increasing performance and reducing potential race conditions. Then use another variable as the index.



          files=(*.jpg)
          total=${#files[@]}
          i=0
          for f in "${files[@]}"; do
          i=$(( i + 1 ))
          echo index $i
          echo total $total
          echo "- Processing file: $f"
          done


          Explanation





          • files=(*.jpg): store the glob into the array $files


          • total=${#files[@]}: read the total into $total


          • i=0: initialise $i to 0.


          • i=$(( i + 1 )): add 1 to $i each loop


          This presumes that the "first" loop is 1. Depending on your opinion, you might want to start at 0 instead.






          share|improve this answer














          I would store the list of files in an array, so that you don't have to read the file system twice, increasing performance and reducing potential race conditions. Then use another variable as the index.



          files=(*.jpg)
          total=${#files[@]}
          i=0
          for f in "${files[@]}"; do
          i=$(( i + 1 ))
          echo index $i
          echo total $total
          echo "- Processing file: $f"
          done


          Explanation





          • files=(*.jpg): store the glob into the array $files


          • total=${#files[@]}: read the total into $total


          • i=0: initialise $i to 0.


          • i=$(( i + 1 )): add 1 to $i each loop


          This presumes that the "first" loop is 1. Depending on your opinion, you might want to start at 0 instead.







          share|improve this answer














          share|improve this answer



          share|improve this answer








          edited 4 hours ago

























          answered 5 hours ago









          Sparhawk

          9,33263991




          9,33263991












          • I need to know the count while the for loop is running to show the progress, not at the end.
            – bman
            5 hours ago










          • @bman I'm not sure what you mean. This will display the count during each loop, not at the end.
            – Sparhawk
            5 hours ago










          • It displays the index, not the total count of files. I think I should use something like this for obtaining the count of files: ls -1q *.jpg | wc -l
            – bman
            5 hours ago










          • @bman Ah got it. that might work generally, but (as you suggest in your question), parsing ls is not great. Give me a minute and I'll edit.
            – Sparhawk
            5 hours ago










          • @bman Okay done.
            – Sparhawk
            4 hours ago


















          • I need to know the count while the for loop is running to show the progress, not at the end.
            – bman
            5 hours ago










          • @bman I'm not sure what you mean. This will display the count during each loop, not at the end.
            – Sparhawk
            5 hours ago










          • It displays the index, not the total count of files. I think I should use something like this for obtaining the count of files: ls -1q *.jpg | wc -l
            – bman
            5 hours ago










          • @bman Ah got it. that might work generally, but (as you suggest in your question), parsing ls is not great. Give me a minute and I'll edit.
            – Sparhawk
            5 hours ago










          • @bman Okay done.
            – Sparhawk
            4 hours ago
















          I need to know the count while the for loop is running to show the progress, not at the end.
          – bman
          5 hours ago




          I need to know the count while the for loop is running to show the progress, not at the end.
          – bman
          5 hours ago












          @bman I'm not sure what you mean. This will display the count during each loop, not at the end.
          – Sparhawk
          5 hours ago




          @bman I'm not sure what you mean. This will display the count during each loop, not at the end.
          – Sparhawk
          5 hours ago












          It displays the index, not the total count of files. I think I should use something like this for obtaining the count of files: ls -1q *.jpg | wc -l
          – bman
          5 hours ago




          It displays the index, not the total count of files. I think I should use something like this for obtaining the count of files: ls -1q *.jpg | wc -l
          – bman
          5 hours ago












          @bman Ah got it. that might work generally, but (as you suggest in your question), parsing ls is not great. Give me a minute and I'll edit.
          – Sparhawk
          5 hours ago




          @bman Ah got it. that might work generally, but (as you suggest in your question), parsing ls is not great. Give me a minute and I'll edit.
          – Sparhawk
          5 hours ago












          @bman Okay done.
          – Sparhawk
          4 hours ago




          @bman Okay done.
          – Sparhawk
          4 hours ago


















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