HardenedBSD/usr.bin/script/script.1
Kyle Evans 8ceac8e13d script: handle terminal resize on SIGWINCH
Add a -w flag to forward terminal resize events on to the child, which
can be useful in some circumstances to avoid terminal corruption.

Reviewed by:	des
Co-authored-by:	Xavier Beaudouin <xavier.beaudouin@klarasystems.com>
Sponsored by:	Modirum MDPay
Sponsored by:	Klara, Inc.
Differential Revision:	https://reviews.freebsd.org/D44167
2024-04-26 11:39:00 -05:00

305 lines
7.2 KiB
Groff

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.Dd October 26, 2022
.Dt SCRIPT 1
.Os
.Sh NAME
.Nm script
.Nd make typescript of terminal session
.Sh SYNOPSIS
.Nm
.Op Fl aeFfkqrw
.Op Fl t Ar time
.Op Ar file Op Ar command ...
.Nm
.Fl p
.Op Fl deq
.Op Fl T Ar fmt
.Op Ar file
.Sh DESCRIPTION
The
.Nm
utility makes a typescript of everything printed on your terminal.
It is useful for students who need a hardcopy record of an interactive
session as proof of an assignment, as the typescript file
can be printed out later with
.Xr lpr 1 .
.Pp
If the argument
.Ar file
is given,
.Nm
saves all dialogue in
.Ar file .
If no file name is given, the typescript is saved in the file
.Pa typescript .
.Pp
If the argument
.Ar command
is given,
.Nm
will run the specified command with an optional argument vector
instead of an interactive shell.
.Pp
The following options are available:
.Bl -tag -width "-F pipe"
.It Fl a
Append the output to
.Ar file
or
.Pa typescript ,
retaining the prior contents.
.It Fl d
When playing back a session with the
.Fl p
flag, do not sleep between records when playing back a timestamped session.
.It Fl e
Accepted for compatibility with
.Em util-linux
.Nm .
The child command exit status is always the exit status of
.Nm .
.It Fl F
Immediately flush output after each write.
This will allow a user to create a named pipe using
.Xr mkfifo 1
and another user may watch the live session using a utility like
.Xr cat 1 .
.It Fl f
Create
.Ar file.filemon
or
.Pa typescript.filemon
using
.Xr filemon 4 .
.It Fl k
Log keys sent to the program as well as output.
.It Fl p
Play back a session recorded with the
.Fl r
flag in real time.
.It Fl q
Run in quiet mode, omit the start, stop and command status messages.
.It Fl r
Record a session with input, output, and timestamping.
.It Fl t Ar time
Specify the interval at which the script output file will be flushed
to disk, in seconds.
A value of 0
causes
.Nm
to flush after every character I/O event.
The default interval is
30 seconds.
.It Fl T Ar fmt
Implies
.Fl p ,
but just reports the time-stamp of each output.
This is very useful for assessing the timing of events.
.Pp
If
.Ar fmt
does not contain any
.Ql %
characters, it indicates the default format:
.Ql %n@ %s [%Y-%m-%d %T]%n ,
which is useful for both tools and humans to read, should be used.
Note that time-stamps will only be output when different from the
previous one.
.It Fl w
Forward terminal size changes on
.Dv SIGWINCH .
.El
.Pp
The script ends when the forked shell (or command) exits (a
.Em control-D
to exit
the Bourne shell
.Pf ( Xr sh 1 ) ,
and
.Em exit ,
.Em logout
or
.Em control-D
(if
.Em ignoreeof
is not set) for the
C-shell,
.Xr csh 1 ) .
.Pp
Certain interactive commands, such as
.Xr vi 1 ,
create garbage in the typescript file.
The
.Nm
utility works best with commands that do not manipulate the screen.
The results are meant to emulate a hardcopy terminal, not an addressable one.
.Sh ENVIRONMENT
The following environment variables are utilized by
.Nm :
.Bl -tag -width SCRIPT
.It Ev SCRIPT
The
.Ev SCRIPT
environment variable is added to the sub-shell.
If
.Ev SCRIPT
already existed in the users environment,
its value is overwritten within the sub-shell.
The value of
.Ev SCRIPT
is the name of the
.Ar typescript
file.
.It Ev SHELL
If the variable
.Ev SHELL
exists, the shell forked by
.Nm
will be that shell.
If
.Ev SHELL
is not set, the Bourne shell
is assumed.
.Pq Most shells set this variable automatically .
.El
.Sh EXAMPLES
Record a simple
.Xr csh 1
session with no additional details like input, output, and timestamping:
.Bd -literal -offset indent
$ SHELL=/bin/csh script
Script started, output file is typescript
% date
Tue Jan 5 15:08:10 UTC 2021
% exit
exit
Script done, output file is typescript
.Ed
.Pp
Now, replay the session recorded in the previous example:
.Bd -literal -offset indent
$ cat ./typescript
Script started on Tue Jan 5 15:08:08 2021
% date
Tue Jan 5 15:08:10 UTC 2021
% exit
exit
Script done on Tue Jan 5 15:08:13 2021
.Ed
.Pp
Record a
.Xr csh 1
session, but this time with additional details like timestamping:
.Bd -literal -offset indent
$ SHELL=/bin/csh script -r
Script started, output file is typescript
% date
Tue Jan 5 15:17:11 UTC 2021
% exit
exit
Script done, output file is typescript
.Ed
.Pp
In order to replay a sessions recorded with the
.Fl r
flag, it is necessary to specify
.Fl p
.Po
.Xr cat 1
will not work because of all the aditional information stored in the session file
.Pc .
Also, let us use
.Fl d
to print the whole session at once:
.Bd -literal -offset indent
$ script -dp ./typescript
Script started on Tue Jan 5 15:17:09 2021
% date
Tue Jan 5 15:17:11 UTC 2021
% exit
exit
Script done on Tue Jan 5 15:17:14 2021
.Ed
.Sh SEE ALSO
.Xr csh 1
.Po
for the
.Em history
mechanism
.Pc ,
.Xr filemon 4
.Sh HISTORY
The
.Nm
command appeared in
.Bx 3.0 .
.Pp
The
.Fl d ,
.Fl p
and
.Fl r
options first appeared in
.Nx 2.0
and were ported to
.Fx 9.2 .
.Sh BUGS
The
.Nm
utility places
.Sy everything
in the log file, including linefeeds and backspaces.
This is not what the naive user expects.
.Pp
It is not possible to specify a command without also naming the script file
because of argument parsing compatibility issues.
.Pp
When running in
.Fl k
mode, echo cancelling is far from ideal.
The slave terminal mode is checked
for ECHO mode to check when to avoid manual echo logging.
This does not
work when the terminal is in a raw mode where
the program being run is doing manual echo.
.Pp
If
.Nm
reads zero bytes from the terminal, it switches to a mode when it
only attempts to read
once a second until there is data to read.
This prevents
.Nm
from spinning on zero-byte reads, but might cause a 1-second delay in
processing of user input.