Unix in DOS

• If you use Unix more than DOS (or after a heavy session with Unix), it might happen to you that you type, say, rm -r <dir> at the DOS prompt. command.com then scolds you that you are doing something fishy. Then only you realize that you have to type deltree instead of rm -r. The batch files provided here sometimes help you in this regard.

• Some DOS commands (once again consider del or deltree) do not support multiple parameters, like

     del file1 file2 file3 dir1 dir2 dir3
  

  The DOS implementation of rm, allows you to do that, as

     rm file1 file2 file3 dir1 dir2 dir3
  

  or as

     rm -r file1 file2 file3 dir1 dir2 dir3
  

  the way you want to delete things.

• These batch files are good examples of how you can write command.com shell programs.

You get here the following batch files. Each of these commands can be executed with a -h switch to see what options it supports and in what format you should specify the command-line parameters.

cat

Concatenates files. By default, it sends its output to console. If you want to redirect it to a file, use the -o option (This is unlike Unix).

cp

Copies one or many files to a directory or a file. When it copies multiple files to a file, it behaves as a concatenation command. Use cp -h to know the details.

df

Shows memory usage. Call df -f to see details on available memory.

grep

This is not the Unix grep. It can find only strings and not regular expressions. Use the options -i for case-insensitive search, -n for printing line-numbers of input files where the string apprears and -v for displaying lines not containing the search string.

ls

Listing of files. Options allowed are: -l, -a, -al and -t. -l shows long-listing. -a shows all files (including hidden ones). -al is -l plus -a. Finally, -t shows files sorted according to time (oldest first). ls.bat supports only one option per call.

man

Essentially calls DOS help command.

mv

Moves single or multiple files to a directory. Type mv -h to know the details.

rm

Removes files and/or directories. The -r option deletes recursively.

uname

Shows some machine-specific details. This does not work exactly the same way the unix uname does.