eof - test a filehandle for its end

- NAME
- SYNOPSIS
- DESCRIPTION

# NAME

eof - test a filehandle for its end

# SYNOPSIS

eof FILEHANDLE

eof ()

eof

# DESCRIPTION

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. (Note that this function actually reads a character and then `ungetc`s it, so isn't very useful in an interactive context.) Do not read from a terminal file (or call `eof(FILEHANDLE)` on it) after end-of-file is reached. File types such as terminals may lose the end-of-file condition if you do.

An `eof` without an argument uses the last file read. Using `eof()` with empty parentheses is very different. It refers to the pseudo file formed from the files listed on the command line and accessed via the `<>` operator. Since `<>` isn't explicitly opened, as a normal filehandle is, an `eof()` before `<>` has been used will cause `@ARGV` to be examined to determine if input is available. Similarly, an `eof()` after `<>` has returned end-of-file will assume you are processing another `@ARGV` list, and if you haven't set `@ARGV`, will read input from `STDIN`; see I/O Operators in the perlop manpage.

In a `while (<>)` loop, `eof` or `eof(ARGV)` can be used to detect the end of each file, `eof()` will only detect the end of the last file. Examples:

        # reset line numbering on each input file
        while (<>) {
            next if /^\s*#/;        # skip comments
            print "$.\t$_";
        } continue {
            close ARGV  if eof;     # Not eof()!
        }

        # insert dashes just before last line of last file
        while (<>) {
            if (eof()) {            # check for end of last file
                print "--------------\n";
            }
            print;
            last if eof();          # needed if we're reading from a terminal
        }

Practical hint: you almost never need to use `eof` in Perl, because the input operators typically return `undef` when they run out of data, or if there was an error.

eof - test a filehandle for its end