Using Cygwin Emacs from DOS prompt

When I'm working in a command line environment in Windows, I normally use notepad for my text editing. On lunix, I prefer emacs. Earlier today I decided it would be nice if I could use emacs in my DOS prompt if I'm in the mood.

By taking advantage of bash's -c flag, it is possible to tell bash to open emacs on the given file(s). After converting the file paths to cygwin appropriate paths, the call is a piece of cake.

I put all this in a bat file on my path so I can call emacs from my DOS prompt at any time:

@echo off
setlocal

set TOEMACS_FILEPATHS=

REM Convert files to full cygwin paths and store in variable
:loopOnInputs
  if "%1"=="" goto :callEmacs

  REM Handy line for storing the output of a command in a variable
  for /f "usebackq delims=" %%i in (`cygpath "%~dpnx1"`) do set ARG_CYGPATH=%%i

  REM Store/append the file path in the variable we'll pass to emacs
  if "%TOEMACS_FILEPATHS%"=="" (
    set TOEMACS_FILEPATHS=%ARG_CYGPATH%
  ) else (
    set TOEMACS_FILEPATHS=%TOEMACS_FILEPATHS% %ARG_CYGPATH%
  )

  REM Pop the argument we just read
  shift
goto :loopOnInputs

REM Run emacs in a new bash shell
:callEmacs
bash -lic "emacs $*" dummy %TOEMACS_FILEPATHS%

:EOF
endlocal

While looping through the input arguments, you'll notice an interesting for loop that I'm using to pipe the output of the cygpath command to a variable. I spent a while trying to figure this out a while ago, and it's been working well for me so far. In short, it loops over every line in the command's output and sets the variable to that line. The delims option changes the delimiter used for separating the command output from spaces and tabs to the end of a line, and since the output of the cygpath command is only one line, we don't have to worry about overwriting the path when there are multiple lines.

Finally, I believe $* is interpreting my dummy argument as $0 or something similar, so that's what the dummy argument is doing there.

Enjoy!

Listing Hidden Files in Bash

I decided it would be useful to have an alias to display all the hidden files in a directory, but wanted a bit more than just a simple alias to 'ls -Ad .**' as this only allows you to list the current directory. Aliasing 'ls -Ad $*.**' worked, but didn't provide any room for error checking regarding trailing directory slashes. There was also the grep option, but that messes with the nice column formatting ls provides so I scrapped that idea.

In short, I decided to write up a function with a short name that I could use as an alias:

# list only hidden files in the given directory(s)
function lh() {

  # if directories were given
  if [ $# -gt 0 ]; then

    # store current dir so we can come back
    startingPath=`pwd`

    # loop through input dirs
    for i in $*; do

      # only list contents for directories
      if [ -d $i ]; then
        cd $i          # cd to the directory
        echo $i:       # print a header
        ls -Ad .**     # list hidden files
      else
        echo Ignoring directory: $i
      fi

      echo    # blank line for readability

    done

    # cd back to your original directory
    cd $startingPath

  else

    # just list hidden files for current directory
    ls -Ad .**

  fi
}

First post!

First post!
Hi all! I've decided to put up this blog to share some of the handy tricks I've come across while working on scripts that you guys might find useful as well. I'm not sure what I'll do about posting some of the scripts I've already come up with, but as I write up new ones, I'll try to post them here. Keep an eye out for interesting coding tidbits as well!