eof - test a filehandle for its end



eof ()



Returns 1 if the next read on FILEHANDLE will return end of file, or if FILEHANDLE is not open. FILEHANDLE may be an expression whose value gives the real filehandle name. (Note that this function actually reads a character and then ungetcs it, so it is not very useful in an interactive context.) Do not read from a terminal file (or call eof on it) after end-of-file is reached. Filetypes such as terminals may lose the end-of-file condition if you do.

An eof without an argument uses the last file read as argument. Empty parentheses () may be used to indicate the pseudo file formed of the files listed on the command line, i.e., eof is reasonable to use inside a while loop to detect the end of only the last file. Use eof or eof without the parentheses to test EACH file in a while (<>) loop. Examples:

    # reset line numbering on each input file
    while (<>) {
	print "$.\t$_";
	close(ARGV) if (eof);	# Not eof().

    # insert dashes just before last line of last file
    while (<>) {
	if (eof()) {
	    print "--------------\n";
	    close(ARGV);	# close or break; is needed if we
				# are reading from the terminal

Practical hint: you almost never need to use eof in Perl, because the input operators return undef when they run out of data.