Truncate a file: Difference between revisions

=={{header|Lua}}==

Lua strings treat each byte as being invariably one whole character (hence the awkwardness of trying to use it with unicode), so it's safe to use string methods to truncate binary data.

<lang Lua>function truncate (filename, length)

local inFile = io.open(filename, 'r')

if not inFile then

error("Specified filename does not exist")

end

local wholeFile = inFile:read("*all")

inFile:close()

if length >= wholeFile:len() then

error("Provided length is not less than current file length")

end

local outFile = io.open(filename, 'w')

outFile:write(wholeFile:sub(1, length))

outFile:close()

end</lang>