`script` is a nice utility for recording terminal sessions.  It spawns
a new shell (by default), and records any activity in that shell:

    $ script /tmp/script
    Script started, file is /tmp/script
    $ ps -u wking | grep script
    12102 pts/7    00:00:00 script
    12103 pts/7    00:00:00 script
    $ pstree 12102
    script───script───bash───pstree
    $ exit
    exit
    Script done, file is /tmp/script

The recorded file stores all the characters sent to the terminal:

    $ cat -v /tmp/script
    Script started on Mon 10 Dec 2012 08:07:17 AM EST
    ^[]0;wking@mjolnir:~^G^[[?1034h^[[01;32mwking@mjolnir^[[01;34m ~ $^[[00m ps -u wking | grep script^M
    12102 pts/7    00:00:00 ^[[01;31m^[[Kscript^[[m^[[K^M
    12103 pts/7    00:00:00 ^[[01;31m^[[Kscript^[[m^[[K^M
    ^[]0;wking@mjolnir:~^G^[[01;32mwking@mjolnir^[[01;34m ~ $^[[00m pstr^G^M
    pstree   pstruct  ^M
    ^[[01;32mwking@mjolnir^[[01;34m ~ $^[[00m pstr^M
    pstree   pstruct  ^M
    ^[[01;32mwking@mjolnir^[[01;34m ~ $^[[00m pstree 12102^M
    scriptM-bM-^TM-^@M-bM-^TM-^@M-bM-^TM-^@scriptM-bM-^TM-^@M-bM-^TM-^@M-bM-^TM-^@bashM-bM-^TM-^@M-bM-^TM-^@M-bM-^TM-^@pstree^M
    ^[]0;wking@mjolnir:~^G^[[01;32mwking@mjolnir^[[01;34m ~ $^[[00m exit^M
    exit^M

    Script done on Mon 10 Dec 2012 08:07:51 AM EST

You can also record timing information in a separate file (this
approach was developed by Joey Hess and posted in [Debian bug
68556][68556]):

    $ script --timing=/tmp/timing /tmp/script
    Script started, file is /tmp/script
    $ echo hello
    hello
    $ exit
    exit
    Script done, file is /tmp/script

The timing file has a “delay in seconds” column and a “number of
characters to send column”:

    $ cat /tmp/timing
    0.671478 67
    0.159100 1
    0.941919 1
    0.149764 1

You can play back a script with timing information:

    $ scriptreplay -t /tmp/timing -s /tmp/script
    …playback…

You can also play it back with altered timing (e.g. in slow motion):

    $ scriptreplay -t /tmp/timing -s /tmp/script -d 0.5
    …half-speed playback playback…

This even works reasonably well with curses applications (`emacs`,
`vi`, …), but information such as window size is not recorded or
replayed.  From util-linux's `scriptreplay(1)`:

> Since the same information is simply being displayed, scriptreplay
> is only guaranteed to work properly if run on the same type of
> terminal the typescript was recorded on.  Otherwise, any escape
> characters in the typescript may be interpreted differently by the
> terminal to which scriptreplay is sending its output.

This means that if you want interoperable replay, you'll want to do
something like

    $ reset
    $ echo "$TERM $LINES $COLUMNS"
    xterm 24 80

early on so folks know how to setup their replay environment.  If
you're using some wonky `$TERM`, you may even want to post your
terminfo:

    $ infocmp
    xterm|xterm terminal emulator (X Window System),
            am, bce, km, mc5i, mir, msgr, npc, xenl,
            colors#8, cols#80, it#8, lines#24, pairs#64,
            acsc=``aaffggiijjkkllmmnnooppqqrrssttuuvvwwxxyyzz{{||}}~~,
    …

The user can compare with their current terminal:

    $ infocmp xterm linux
    comparing xterm to linux.
        comparing booleans.
            ccc: F:T.
            eo: F:T.
            …
        comparing numbers.
            cols: 80, NULL.
            lines: 24, NULL.
            ncv: NULL, 18.
        …

It would be nice if there was an `iconv`-style converter to translate
between terminal operation encodings, but I haven't found one yet.
[[Screen]] [does something like this internally][screen], and their
[list of control sequences][seq] is a useful reference.  I've started
work on an [[escape-sequence-to-HTML
converter|script/script-publish.py]], in case you want to play around
with these conversions in [[Python]].


[68556]: http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=68556
[screen]: http://www.gnu.org/software/screen/manual/html_node/Virtual-Terminal.html
[seq]: http://www.gnu.org/software/screen/manual/html_node/Control-Sequences.html#Control-Sequences