How to loop over files in directory and change path and add suffix to filename

Question

I need to write a script that starts my program with different arguments  but I m new to Bash  I start my program with     MyProgram exe Data data1 txt  Logs data1 Log txt    Here is the pseudocode for what I want to do   for each filename in  Data do   for int i   0  i   3  i         MyProgram exe Data filename txt Logs filename Log i  txt   end for end for   So I m really puzzled how to create second argument from the first one  so it looks like dataABCD Log1 txt and start my program

User · Answer

Sorry for necromancing the thread  but whenever you iterate over files by globbing  it s good practice to avoid the corner case where the glob does not match  which makes the loop variable expand to the  un-matching  glob pattern string itself    For example    for filename in Data   txt  do       -e   filename       continue           rest of the loop body done   Reference  Bash Pitfalls

User · Answer

A couple of notes first  when you use Data data1 txt as an argument  should it really be  Data data1 txt  with a leading slash   Also  should the outer loop scan only for  txt files  or all files in  Data  Here s an answer  assuming  Data data1 txt and  txt files only      bin bash for filename in  Data   txt  do     for   i 0  i lt  3  i      do           MyProgram exe   filename   Logs   basename   filename   txt  Log i txt      done done   Notes     Data   txt expands to the paths of the text files in  Data  including the  Data  part           runs a shell command and inserts its output at that point in the command line basename somepath  txt outputs the base part of somepath  with  txt removed from the end  e g   Data file txt -  file    If you needed to run MyProgram with Data file txt instead of  Data file txt  use    filename     to remove the leading slash  On the other hand  if it s really Data not  Data you want to scan  just use for filename in Data   txt

User · Answer

Looks like you re trying to execute a windows file   exe  Surely you ought to be using powershell  Anyway on a Linux bash shell a simple one-liner will suffice     home    for filename in  Data   txt  do for i in  0  3   do   MyProgam exe  Data filenameLogs  filename log i txt  done done   Or in a bash     bin bash  for filename in  Data   txt      do      for i in  0  3           do   MyProgam exe Data filename txt Logs  filename log i txt        done   done

User · Answer

for file in Data   txt do     for   i   0  i  lt  3  i         do         name   file              base   name  txt            MyProgram exe   file  Logs    base  Log i txt      done done   The name   file      substitution  shell parameter expansion  removes the leading pathname up to the last     The base   name  txt  substitution removes the trailing  txt   It s a bit trickier if the extensions can vary

User · Answer

You can use finds null separated output option with read to iterate over directory structures safely      bin bash find   -type f -print0   while IFS  read -r -d    0  file     do echo   file    done   So for your case      bin bash find   -maxdepth 1 -type f  -print0   while IFS  read -r -d    0  file  do   for   i 0  i lt  3  i      do       MyProgram exe   file   Logs    basename   file     i   txt    done done   additionally      bin bash while IFS  read -r -d    0  file  do   for   i 0  i lt  3  i      do       MyProgram exe   file   Logs    basename   file     i   txt    done done  lt   lt  find   -maxdepth 1 -type f  -print0    will run the while loop in the current scope of the script   process   and allow the output of find to be used in setting variables if needed

[bash] How to loop over files in directory and change path and add suffix to filename

Examples related to bash

Examples related to for-loop

Examples related to filenames

Examples related to glob