The asa(1) utility reads text with ASA carriage-control
characters from the files specified as its command arguments, or
standard input if none are specified, and converts them into line
printer control sequences.
These control characters are traditionally used in Fortran
programs.
The first character of every line is removed from input, and the
following actions are performed according to which character is
removed.
If the character removed is:
<space>
The rest of the line is output without change
0
A <newline> is output, then the rest of the input
line
1
A <form feed> is output, then the rest of the input
line
+
An attempt is made to overstrike the previous line with the one
following the character; this can be used for emphasis
<any other character>
The same actions as for a <space> are performed; this is
an extension of the POSIX.2 standard
The overstriking generated may be removed by piping the output
through col -b.
Tabs in the input file are expanded to a width of eight.
It is not be possible to use the asa(1) filter for
interactive use in Fortran programs because of the semantics of the
+ character, and because I/O is buffered.