replace tab characters by spaces in your text files with a free open source command line tool for Windows, Mac OS X, Linux and Raspberry Pi.

- download the free Swiss File Knife Base from Sourceforge.
- open the Windows CMD command line, Mac OS X Terminal or Linux shell.
- OS X : type mv sfk-mac-i686.exe sfk and chmod +x sfk then ./sfk
- Linux: type mv sfk-linux.exe sfk    and chmod +x sfk then ./sfk
  OS X and Linux syntax may differ, check the help within the tool.

sfk detab=tabsize dir ext1 [ext2 ...] [-to outmask]

replace tabs by spaces within file(s) or text stream.

options
   -to outmask   do not overwrite original files, but write
                 to output files according to outmask, e.g.
                 -to tmp\$path\$base.$ext or -to tmp\$file
   -yes          if files are selected, really (re)write them.
                 without -yes, detab is only simulated.
   -memlimit=n   process files with up to n mbytes (default=300).
   -nowarn       do not tell about skipped or unreadable files.

see also
   sfk scantab   list files containing TAB characters.
   sfk help opt  how to change the memlimit permanently.
   sfk view      a text file viewer that can show all TAB
                 characters in blue by pressing CTRL+T.

web reference
   http://stahlworks.com/sfk-detab

examples
   sfk detab=3 sources .cpp .hpp
      replace tabs by up to 3 blanks, within all .cpp and .hpp
      files of directory tree "sources".

   sfk select -dir src -file .java +detab=4 -to tmp\$file
      list all .java files of src, then detab with tabsize 4,
      writing all outputs to directory tree "tmp".

   sfk detab=4 src .java -relnames -to tmp\$file
      nearly the same, however stripping the "src" input directory
      name from output file paths (not possible with "+detab" form).

   sfk filter mytext.txt +detab=8
      detab content of a single file to the console.
 

to find how many files would need detabbing, type for example:

   sfk scantab testfiles .hpp .cpp .txt
     -> scans directory testfiles, and all subdirectories,
        for .hpp, .cpp and .txt files containing tab characters.

   example output:
      list of files containing tabs:
      testfiles\Formats\01-native-tab-crlf.txt
      testfiles\Formats\02-crlf.txt
      testfiles\Formats\03-native-tab-lf.txt
      testfiles\Formats\04-lf.txt
      testfiles\Formats\08-head-tail.txt
      testfiles\Formats\20-tab-data-line.txt
      6 files of 32 contain tabs.

to view TAB characters in your files interactively like this:

   

   - download the free text browser Depeche View Base.
   - click on "Open", select the folder containing your text files.
   - click on the "showtab" button in the right bottom corner.

   All TAB characters will be shown in blue, and all blanks in yellow.

to search for TAB characters interactively:

   Within Depeche View, use the TAB keyword in your queries, e.g.

   -  type "TAB " to find all TAB characters.
      (Type it all uppercase, and don't forget the blank after TAB)

   -  type "TAB }" to find all curly brackets } preceeded by a tab:

   

   -  type "foo TAB bar" to find the word combination "foo" and "bar"
      with exactly one TAB character inbetween. Note that the blanks
      around "TAB" are not used in the search.

read more about all sfk functions here.