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.






shell-script







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.






    shell-script







    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.






      shell-script







      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




      shell-script






      share|improve this question















      share|improve this question













      share|improve this question




      share|improve this question








      edited Jan 4 at 3:02







      bman

















      asked Jan 4 at 2:49









      bmanbman

      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
            Jan 4 at 2:55










          • @bman I'm not sure what you mean. This will display the count during each loop, not at the end.
            – Sparhawk
            Jan 4 at 2:56










          • 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
            Jan 4 at 2:58










          • @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
            Jan 4 at 2:59










          • @bman Okay done.
            – Sparhawk
            Jan 4 at 3:05











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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
            Jan 4 at 2:55










          • @bman I'm not sure what you mean. This will display the count during each loop, not at the end.
            – Sparhawk
            Jan 4 at 2:56










          • 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
            Jan 4 at 2:58










          • @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
            Jan 4 at 2:59










          • @bman Okay done.
            – Sparhawk
            Jan 4 at 3:05
















          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
            Jan 4 at 2:55










          • @bman I'm not sure what you mean. This will display the count during each loop, not at the end.
            – Sparhawk
            Jan 4 at 2:56










          • 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
            Jan 4 at 2:58










          • @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
            Jan 4 at 2:59










          • @bman Okay done.
            – Sparhawk
            Jan 4 at 3:05














          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 Jan 4 at 3:05

























          answered Jan 4 at 2:54









          SparhawkSparhawk

          9,34663991




          9,34663991












          • I need to know the count while the for loop is running to show the progress, not at the end.
            – bman
            Jan 4 at 2:55










          • @bman I'm not sure what you mean. This will display the count during each loop, not at the end.
            – Sparhawk
            Jan 4 at 2:56










          • 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
            Jan 4 at 2:58










          • @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
            Jan 4 at 2:59










          • @bman Okay done.
            – Sparhawk
            Jan 4 at 3:05


















          • I need to know the count while the for loop is running to show the progress, not at the end.
            – bman
            Jan 4 at 2:55










          • @bman I'm not sure what you mean. This will display the count during each loop, not at the end.
            – Sparhawk
            Jan 4 at 2:56










          • 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
            Jan 4 at 2:58










          • @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
            Jan 4 at 2:59










          • @bman Okay done.
            – Sparhawk
            Jan 4 at 3:05
















          I need to know the count while the for loop is running to show the progress, not at the end.
          – bman
          Jan 4 at 2:55




          I need to know the count while the for loop is running to show the progress, not at the end.
          – bman
          Jan 4 at 2:55












          @bman I'm not sure what you mean. This will display the count during each loop, not at the end.
          – Sparhawk
          Jan 4 at 2:56




          @bman I'm not sure what you mean. This will display the count during each loop, not at the end.
          – Sparhawk
          Jan 4 at 2:56












          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
          Jan 4 at 2:58




          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
          Jan 4 at 2:58












          @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
          Jan 4 at 2:59




          @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
          Jan 4 at 2:59












          @bman Okay done.
          – Sparhawk
          Jan 4 at 3:05




          @bman Okay done.
          – Sparhawk
          Jan 4 at 3:05


















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