Loop through all the files with a specific extension

Question

for i in   ls  do     if    i      java    then         echo  I do something with the file  i      fi done   I want to loop through each file in the current folder and check if it matches a specific extension  The code above doesn t work  do you know why

User · Answer

the correct answer is  chepner s   EXT java for i in     EXT   do         done   however  here s a small trick to check whether a filename has a given extensions   EXT java for i in    do     if      i         i    EXT      then         echo  I do something with the file  i      fi done

User · Answer

No fancy tricks needed   for i in   java  do       -f   i       break         done   The guard ensures that if there are no matching files  the loop will exit without trying to process a non-existent file name   java  In bash  or shells supporting something similar   you can use the nullglob option to simply ignore a failed match and not enter the body of the loop   shopt -s nullglob for i in   java  do         done

User · Answer

Loop through all files ending with   img   bin   txt suffix  and print the file name   for i in   img   bin   txt  do   echo   i  done   Or in a recursive manner  find also in all subdirectories    for i in  find   -type f -name    img  -o -name    bin  -o -name    txt    do   echo   i  done

User · Answer

I agree withe the other answers regarding the correct way to loop through the files  However the OP asked      The code above doesn t work  do you know why    Yes   An excellent article  What is the difference between test    and        explains in detail that among other differences  you cannot use expression matching or pattern matching within the test command  which is shorthand for        Feature            new test       old test             Example  Pattern matching       or         not available         name   a        echo  name does not start with an  a    name   Regular Expression                not available          date      Fri       13       echo  It s Friday the 13th   matching   So this is the reason your script fails  If the OP is interested in an answer with the    syntax  which has the disadvantage of not being supported on as many platforms as the   command   I would be happy to edit my answer to include it   EDIT  Any protips for how to format the data in the answer as a table would be helpful

User · Answer

Recursively add subfolders   for i in  find   -name    java  -type f   do     echo   i  done

User · Answer

I found this solution to be quite handy  It uses the -or option in find   find   -name    tex -or -name    png  -or -name    pdf   It will find the files with extension tex  png  and pdf

User · Answer

as  chepner says in his comment you are comparing  i to a fixed string   To expand and rectify the situation you should use       with the regex operator     eg   for i in   ls  do     if     i        java     then         echo  I want to do something with the file  i      fi done   the regex to the right of    is tested against the value of the left hand operator and should not be quoted    quoted will not error but will compare against a fixed string and so will most likely fail   but  chepner  s answer above using glob is a much more efficient mechanism

[bash] Loop through all the files with a specific extension

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