OS X (Apple)

#!/bin/sh

storyboardExt=".storyboard"
stringsExt=".strings"
newStringsExt=".strings.new"
oldStringsExt=".strings.old"
localeDirExt=".lproj"
baseLprojDir="Base${localeDirExt}"

echo "${baseLprojDir}"

# Find Base.lproj path
baseLprojPath=`find . -name "${baseLprojDir}" -print`
echo "baseLprojPath= ${baseLprojPath}"

#Find storyboard file full path inside project folder
for storyboardPath in `find "${baseLprojPath}" -name "*${storyboardExt}" -print`
do
    echo "storyboardPath= ${storyboardPath}"

    # Get Base strings file path
    baseStoryboardStringsPath=$(echo "$storyboardPath" | sed "s/$storyboardExt/$stringsExt/")
    echo "baseStoryboardStringsPath= ${baseStoryboardStringsPath}"

    storyboardStringsFile=$(basename "$baseStoryboardStringsPath" "${stringsExt}")
    echo "storyboardStringsFile= ${storyboardStringsFile}"

    baseStringsArray["${storyboardStringsFile}"]="${baseStoryboardStringsPath}"
    echo ${baseStringsArray[$storyboardStringsFile]}
done

for baseStringsPath in "${baseStringsArray[@]}"
do
    echo "baseStringsArray= $baseStringsPath"
done

Base.lproj
baseLprojPath= ./SingleStoryboardLocalize/Base.lproj
storyboardPath= ./SingleStoryboardLocalize/Base.lproj/MainStoryboard_iPad.storyboard
baseStoryboardStringsPath= ./SingleStoryboardLocalize/Base.lproj/MainStoryboard_iPad.strings
storyboardStringsFile= MainStoryboard_iPad
./SingleStoryboardLocalize/Base.lproj/MainStoryboard_iPad.strings
storyboardPath= ./SingleStoryboardLocalize/Base.lproj/MainStoryboard_iPhone.storyboard
baseStoryboardStringsPath= ./SingleStoryboardLocalize/Base.lproj/MainStoryboard_iPhone.strings
storyboardStringsFile= MainStoryboard_iPhone
./SingleStoryboardLocalize/Base.lproj/MainStoryboard_iPhone.strings
baseStringsArray= ./SingleStoryboardLocalize/Base.lproj/MainStoryboard_iPhone.strings