script: support multi-stream logging

[thirdparty/util-linux.git] / term-utils / script.1

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.\"	@(#)script.1	6.5 (Berkeley) 7/27/91
.\"
.TH SCRIPT "1" "June 2014" "util-linux" "User Commands"
.SH NAME
script \- make typescript of terminal session
.SH SYNOPSIS
.B script
[options]
.RI [ file ]
.SH DESCRIPTION
.B script
makes a typescript of everything displayed 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
.BR lpr (1).
Since version 2.35
.B script
supports multiple streams and allows to log input and output to separate
files or all the one file.
.PP
If the argument
.I file
or option \fB\-\-log\-out\fR \fIfile\fR is given,
.B script
saves the dialogue in this
.IR file .
If no filename is given, the dialogue is saved in the file
.BR typescript .
.SH OPTIONS
Below, the \fIsize\fR argument may be followed by the multiplicative
suffixes KiB (=1024), MiB (=1024*1024), and so on for GiB, TiB, PiB, EiB, ZiB and YiB
(the "iB" is optional, e.g. "K" has the same meaning as "KiB"), or the suffixes
KB (=1000), MB (=1000*1000), and so on for GB, TB, PB, EB, ZB and YB.
.TP
\fB\-a\fR, \fB\-\-append\fR
Append the output to
.I file
or to
.BR typescript ,
retaining the prior contents.
.TP
\fB\-c\fR, \fB\-\-command\fR \fIcommand\fR
Run the
.I command
rather than an interactive shell.  This makes it easy for a script to capture
the output of a program that behaves differently when its stdout is not a
tty.
.TP
\fB\-e\fR, \fB\-\-return\fR
Return the exit code of the child process.  Uses the same format as bash
termination on signal termination exit code is 128+n.  The exit code of
the child process is always stored in type script file too.
.TP
\fB\-f\fR, \fB\-\-flush\fR
Flush output after each write.  This is nice for telecooperation: one person
does `mkfifo foo; script -f foo', and another can supervise real-time what is
being done using `cat foo'.
.TP
\fB\-\-force\fR
Allow the default output destination, i.e. the typescript file, to be a hard
or symbolic link.  The command will follow a symbolic link.
.TP
\fB\-B\fR, \fB\-\-log\-io\fR \fIfile\fR
Log input and output to the same
\fIfile\fR.  Note, this option makes sense only if \fB\-\-log\-timing\fR is
also specified, otherwise it's impossible to separate output and input streams from
the log \fIfile\fR.
.TP
\fB\-I\fR, \fB\-\-log\-in\fR \fIfile\fR
Log input to the \fIfile\fR.  The log output is disabled if only \fB\-\-log\-in\fR
specified.
.sp
Use this logging functionality carefully as it logs all input, including input 
when terminal has disabled echo flag (for example it log passwords in the input).
.TP
\fB\-O\fR, \fB\-\-log\-out\fR \fIfile\fR
Log output to the \fIfile\fR. The default is to log output to the file with
name 'typescript' if the option \fB\-\-log\-out\fR or \fB\-\-log\-in\fR is not
given.  The log output is disabled if only \fB\-\-log\-in\fR specified.
.TP
\fB\-T\fR, \fB\-\-log\-timing\fR \fIfile\fR
Log timing information to the \fIfile\fR. Two timing file formats are supporte
now.  The classic format is used when only one stream (input or output) logging
is enabled. The multi-stream format is used on \fB\-\-log\-io\fR or when
\fB\-\-log\-in\fR and \fB\-\-log\-out\fR are used together.
.sp
.RS
.B Classic format
.PP
The log contains two fields, separated by a space.  The first
field indicates how much time elapsed since the previous output.  The second
field indicates how many characters were output this time.
.sp
.B Multi-stream format
.PP
The first field is entry type itentifier ('I'nput, 'O'utput, 'H'eader, 'S'ignal).
The socond field is how much time elapsed since the previous entry, and rest of the entry is type specific data.
.RE
.TP
\fB\-o\fR, \fB\-\-output-limit\fR \fIsize\fR
Limit the size of the typescript and timing files to
.I size
and stop the child process after this size is exceeded.  The calculated
file size does not include the start and done messages that the
.B script
command prepends and appends to the child process output.
Due to buffering, the resulting output file might be larger than the specified value.
.TP
\fB\-q\fR, \fB\-\-quiet\fR
Be quiet (do not write start and done messages to standard output).
.TP
\fB\-t\fR[\fIfile\fR], \fB\-\-timing\fR[=\fIfile\fR]
Output timing data to standard error, or to
.I file
when given.  This option is deprecated in favour of \fB\-\-log\-timing\fR where
the \fIfile\fR argument is not optional.
.TP
\fB\-V\fR, \fB\-\-version\fR
Display version information and exit.
.TP
\fB\-h\fR, \fB\-\-help\fR
Display help text and exit.
.SH NOTES
The script ends when the forked shell exits (a
.I control-D
for the Bourne shell
.RB ( sh (1p)),
and
.IR exit ,
.I logout
or
.I control-d
(if
.I ignoreeof
is not set) for the
C-shell,
.BR csh (1)).
.PP
Certain interactive commands, such as
.BR vi (1),
create garbage in the typescript file.
.B script
works best with commands that do not manipulate the screen, the results are
meant to emulate a hardcopy terminal.
.PP
It is not recommended to run
.B script
in non-interactive shells.  The inner shell of
.B script
is always interactive, and this could lead to unexpected results.  If you use
.B script
in the shell initialization file, you have to avoid entering an infinite
loop.  You can use for example the \fB\%.profile\fR file, which is read
by login shells only:
.RS
.RE
.sp
.na
.RS
.nf
if test -t 0 ; then
    script
    exit
fi
.fi
.RE
.ad
.PP
You should also avoid use of script in command pipes, as
.B script
can read more input than you would expect.
.PP
.SH ENVIRONMENT
The following environment variable is utilized by
.BR script :
.TP
.B SHELL
If the variable
.B SHELL
exists, the shell forked by
.B script
will be that shell.  If
.B SHELL
is not set, the Bourne shell is assumed.  (Most shells set this variable
automatically).
.SH SEE ALSO
.BR csh (1)
(for the
.I history
mechanism),
.BR scriptreplay (1)
.SH HISTORY
The
.B script
command appeared in 3.0BSD.
.SH BUGS
.B script
places
.I everything
in the log file, including linefeeds and backspaces.  This is not what the
naive user expects.
.PP
.B script
is primarily designed for interactive terminal sessions.  When stdin
is not a terminal (for example: \fBecho foo | script\fR), then the session
can hang, because the interactive shell within the script session misses EOF and
.B script
has no clue when to close the session.  See the \fBNOTES\fR section for more information.
.SH AVAILABILITY
The script command is part of the util-linux package and is available from
.UR https://\:www.kernel.org\:/pub\:/linux\:/utils\:/util-linux/
Linux Kernel Archive
.UE .