Replace more than one consecutive spaces with tab in files on both Linux and Mac OS X.

spaces2tab.sh

#!/bin/sh

# Replace more than one consecutive spaces with tab in files on both Linux and Mac OS X. 
# You need to install gnu-sed on Mac OS X for this to work. 
# Usage: spaces2tab.sh [file ...]
# See also: http://azaleasays.com/2014/03/07/os-x-sed-does-not-recognize-tab-character/


if [ "$(uname -s)" == "Darwin" ] # If the system is Mac OS X
then
   mysed="gsed"
else
   mysed="sed"
fi

for inputfile in "$@"
do
    #echo processing $inputfile
    $mysed -i 's/ \+ /\t/g' "$inputfile"
done