Interdata_v6/usr/doc/man/man1/log.1

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.th LOG I 8/12/77
.sh NAME
log - hardcopy log of terminal session
.sh SYNOPSIS
log [ file ]
.sh DESCRIPTION
After
.it log
is executed, all subsequent terminal I/O is
logged onto
.it file.
Both input and output are copied onto the file,
interspersed in the same order as they appear
on the terminal.

If
.it file
is omitted,
.it log
forces the shell's standard output to the terminal
(file descriptor 2)
and logs I/O on the
.it log
command's standard output.
Thus
.it log
can be used as a filter; e.g.
.ti +10
% log | opr

To terminate logging, type
.it ctrl-d.
.sh AUTHOR
R Miller
.br
University of Wollongong
.sh BUGS
Since
.it log
is implemented with pipes, any program which tries to
read from fd 1 or write to fd 0
(e.g. Interdata BASIC II)
cannot be logged.