How to clear search history in sidebar?

rm -rf "/Volumes/extfat32volume/._filename"

set originalFile to choose file with prompt "Choose a document to clear from sidebar history:"
set originalPOSIXFilePath to POSIX path of originalFile
--Set the name of your FAT32 volume in the quotes on the next line
set otherDisk to "NO NAME"
tell application "Finder"
	set originalFilePath to container of originalFile as text
	copy file originalFile to disk otherDisk
end tell
set originalFileName to name of (info for originalFile)
set destinationFullPath to otherDisk & ":" & originalFileName
set destinationMDFullPath to otherDisk & ":._" & originalFileName
set copiedFile to alias destinationFullPath
set copiedFileMD to alias destinationMDFullPath
tell application "Finder"
	delete originalFile
	delete copiedFileMD
	copy file copiedFile to alias originalFilePath
	delete copiedFile
end tell
delay 0.5
--last part modifies the POSIX last access time to complete the job
do shell script "touch -a -t 200901010715 " & originalPOSIXFilePath

on hide_item(fileToProcess)
	set posixPath to POSIX path of fileToProcess
	do shell script "touch -a -t 200901010730 " & "'" & posixPath & "'"
	do shell script "gzip " & "'" & posixPath & "'"
	do shell script "gzip -d " & "'" & posixPath & ".gz'"
end hide_item

on run
	set anItem to choose file with prompt "Choose a document to clear from sidebar history:"
	hide_item(anItem)
end run

on open itemsToHide
	repeat with anItem in itemsToHide
		hide_item(anItem)
	end repeat
end open

on hide_item(fileToProcess)
	set posixPath to replaceChar(POSIX path of fileToProcess, "\"", "\\\"")
	do shell script "touch -a -t 200901010730 " & "\"" & posixPath & "\""
	do shell script "ditto --norsrc \"" & posixPath & "\" tmpfile.jpg && mv tmpfile.jpg " & "\"" & posixPath & "\""
end hide_item

on replaceChar(theString, oldChar, newChar)
	set oldDelimiters to AppleScript's text item delimiters
	set AppleScript's text item delimiters to oldChar
	set theArray to every text item of theString
	set theNewString to ""
	repeat with i from 1 to length of theArray
		set stringPart to item i of theArray
		set theNewString to theNewString & stringPart
		if i is less than length of theArray then set theNewString to theNewString & newChar
	end repeat
	return theNewString
end replaceChar

on run
	set anItem to choose file with prompt "Choose a document to clear from sidebar history:" without invisibles
	hide_item(anItem)
end run

on open itemsToHide
	repeat with anItem in itemsToHide
		hide_item(anItem)
	end repeat
end open

--Main handler for the script.
on hideItem(pathAlias)
	--Get the path to use in the shell command from the alias of the file.
	set posixPath to POSIX path of pathAlias
	set quotedPosixPath to quoted form of posixPath
	--Checks that the path is to a file and not a directory and proceeds.
	if isPOSIXDirectoryPath(posixPath) is false then
		do shell script "touch -a -t 200901010730 " & quotedPosixPath & " && ditto --norsrc " & quotedPosixPath & " tmpfile.jpg && mv tmpfile.jpg " & quotedPosixPath
	else
		do shell script "touch -a -t 200901010730 " & quotedPosixPath & " && ditto --norsrc " & quotedPosixPath & " tmpfile && rm -rf " & quotedPosixPath & " && mv tmpfile " & quotedPosixPath
	end if
end hideItem

-- Checks whether the POSIX path given points to a directory or a file. True if directory.
on isPOSIXDirectoryPath(thePath)
	if last character of thePath is "/" then
		set theResult to true
	else
		set theResult to false
	end if
	return theResult
end isPOSIXDirectoryPath

-- Displays a prompt to select a file in the event that the script is double-clicked.
on run
	set anItem to choose file with prompt "Choose a document to clear from sidebar history:" without invisibles
	hideItem(anItem)
end run

-- Provides droplet functionality.
on open itemsToHide
	repeat with anItem in itemsToHide
		hideItem(anItem)
	end repeat
end open