(notonline)-->
bool first = true
integer fn = open("fasta.txt","r")
if fn=-1 then ?9/0 end if
while true do
object line = trim(gets(fn))
if atom(line) then puts(1,"\n") exit end if
if length(line) then
if line[1]=='>' then
if not first then puts(1,"\n") end if
printf(1,"%s: ",{line[2..$]})
first = false
elsif first then
printf(1,"Error : File does not begin with '>'\n")
exit
elsif not find_any(" \t",line) then
puts(1,line)
else
printf(1,"\nError : Sequence contains space(s)\n")
exit
end if
end if
end while
close(fn)