Provided by: byobu_5.77-0ubuntu1.2_all 
NAME
byobu - wrapper script for seeding a user's byobu configuration and launching a text based window manager
(either screen or tmux)
SYNOPSIS
byobu [screen options]
byobu-screen [screen options]
byobu-tmux [tmux options]
Options to byobu are simply passed through screen(1) or tmux(1).
DESCRIPTION
byobu is a script that launches a text based window manager (either screen(1) or tmux(1)) in the byobu
configuration. This enables the display of system information and status notifications within two lines
at the bottom of the screen session. It also enables multiple tabbed terminal sessions, accessible
through simple keystrokes.
byobu currently defaults to using tmux(1) (if present) as the backend, however, this can be overridden
with the byobu-select-backend(1) utility.
Note that BYOBU_CONFIG_DIR=$XDG_CONFIG_HOME/byobu if defined, and $HOME/.byobu otherwise.
BACKGROUND COLORS
The background colors of the byobu status lines can be adjusted by editing the files $HOME/.byobu/color
(for byobu-screen) and $HOME/.byobu/color.tmux (for byobu-tmux). The command Ctrl-Shift-F5 will change
the background to a randomly selected color when running in byobu-tmux mode. Simply remove those files
to return to the default color configuration.
STATUS NOTIFICATIONS
byobu supports a number of unique and interesting status notifications across the lowest two lines in the
screen. Each status notification item is independently configurable, enabled and disabled by the
configuration utility. The guide below helps identify each status item (in alphabetical order):
apport - symbol displayed if there are pending crash reports; {!} symbol displayed on the lower bar
toward the left, in black on an orange background
arch - system architecture; displayed on the lower bar toward the left, in the default text color on the
default background color
battery - battery information; display on the lower bar toward the right; - indicates discharging, +
indicates charging, = indicates fully charged; when charging or discharging, the current battery
capacity as a percentage is displayed; the colours green, yellow, and red are used to give further
indication of the battery's charge state; you may override the detected battery by setting
BATTERY=/proc/acpi/battery/BAT0 in $BYOBU_CONFIG_DIR/statusrc
cpu_count - the number of cpu's or cores on the system; displayed in the lower bar toward the right in
the default text color on the default background, followed by a trailing 'x'
cpu_freq - the current frequency of the cpu in GHz; displayed in the lower bar toward the right in white
text on a light blue background
cpu_temp - the cpu temperature in Celsius (default) or Fahrenheit, configure TEMP=F or TEMP=C in
$BYOBU_CONFIG_DIR/statusrc; displayed in the lower bar toward the right in yellow text on a black
background; you may override the detected cpu temperature device by setting
MONITORED_TEMP=/proc/acpi/whatever in $BYOBU_CONFIG_DIR/statusrc
custom - user defined custom scripts; must be executable programs of any kind in $BYOBU_CONFIG_DIR/bin;
must be named N_NAME, where N is the frequency in seconds to refresh the status indicator, and NAME is
the name of the script; N should not be less than 5 seconds; the script should echo a small amount of
text to standard out, standard error is discarded; the indicator will be displayed in the lower panel, in
default colors, unless you manually specify the colors in your script's output; BEWARE, cpu-intensive
custom scripts may impact your overall system performance and could upset your system administrator! In
fact, you can easily copy and modify any status script usually found in /usr/lib/byobu/* to your local
$HOME/.byobu/ directory.
Example: $BYOBU_CONFIG_DIR/bin/1000_uname
#!/bin/sh
printf "\005{= bw}%s\005{-}" "$(uname -r)"
date - the system date in YYYY-MM-DD format, or you can set this to any valid strftime(3) you like in
$BYOBU_CONFIG_DIR/datetime; displayed in the lower on the far right in the default text color on the
default background
disk - total disk space available and total used on / directory; displayed in the lower bar on the far
right in white text on a light purple background; override the default directory by specifying an
alternate mount point with MONITORED_DISK=/wherever in $BYOBU_CONFIG_DIR/statusrc
disk_io - instantaneous read/write througput in kB/s or MB/s over the last 3 seconds; displayed in the
lower bar toward the right in white text on a light purple background with a leading '<' sign indicating
'read speed' and '>' sign indicating 'write speed'; override the default monitored disk by specifying an
alternate device with MONITORED_DISK=/dev/sdb, and override the default DISK_IO_THRESHOLD=50 (kB/s) in
$BYOBU_CONFIG_DIR/statusrc
distro - OS/distribution name of the release running on the current system as reported by lsb_release(1)
or /etc/issue; displayed in the lower bar in bold black text toward the left on a grey background; you
may override the detected release with DISTRO=Whatever in $BYOBU_CONFIG_DIR/statusrc
ec2_cost - an estimation of the cost of the current boot of the system in terms of the Amazon EC2 billing
model; displayed in the lower bar toward the right in green text on a black background; the monetary
units are US Dollars '$'; this plugin only works when an AWS-compatible metadata server is available at
http://169.254.169.254
entropy - a count of the system's current entropy in bytes; displayed in the lower bar toward the right
in yellow text on a dark grey background; there is a leading 'e' to indicate 'entropy'
raid - note very prominently if there is a RAID failure detected, in red blinking text on a white
background; the term 'RAID' notes that there is something wrong with the RAID, and if there is a
rebuild/resync in progress, the percent complete is also shown
rcs_cost - an estimation of the cost of the current boot of the system in terms of the Rackspace Cloud
Server billing model; displayed in the lower bar toward the right in green text on a black background;
there is a leading '~' to indicate that this is an estimation, and the monetary units are US Dollars '$'
fan_speed - cpu or system fan speed as reported by lm-sensors; displayed in the lower bar toward the
right in black text on a grey background; there is a trailing 'rpm' for units; you may override the
detected fan by setting FAN=/sys/path/to/your/fan1_input in $BYOBU_CONFIG_DIR/statusrc
hostname - the hostname of the system; displayed in the upper bar on the far right in bold black text on
a grey background; there is a leading '@' symbol if the username status is also enabled
ip_address - the IPv4 address of the system in dotted decimal form; displayed in the upper bar on the far
right in bold black text on a grey background; you can override and display your IPv6 address by setting
'IPV6=1', and you can show your external ip address by setting 'IP_EXTERNAL=1' in
$BYOBU_CONFIG_DIR/statusrc
ip_address4 - the IPv4 address of the system in dotted decimal form; displayed in the upper bar on the
far right in bold black text on a grey background; you can show your external ip address by setting
'IP_EXTERNAL=1' in $BYOBU_CONFIG_DIR/statusrc
ip_address6 - the IPv6 address of the system; displayed in the upper bar on the far right in bold black
text on a grey background; you can show your external ip address by setting 'IP_EXTERNAL=1' in
$BYOBU_CONFIG_DIR/statusrc
load_average - the system load average over the last 1 minute; displayed in the lower bar toward the
right in black text on a yellow background
logo - an approximation of the current operating system's logo; displayed in the lower bar on the far
left; you may customize this logo by setting a chosen logo in $BYOBU_CONFIG_DIR/logo, or you may override
this with LOGO=:-D in $BYOBU_CONFIG_DIR/statusrc
mail - system mail for the current user; the letter '[M]' is displayed in the lower bar toward the left
in black text on a grey background
memory - total memory available and used percentage in the system; displayed in the lower bar toward the
right in white text on a green background
menu - a simple indicator directing new users to use the F9 keybinding to access the byobu menu
network - instantaneous upload/download bandwidth in [GMk]bps over the last 3 seconds; nothing is
displayed if traffic is 0; displayed in the lower bar toward the left in white text on a purple
background with a leading '^' sign indicating 'up' and 'v' sign indicating 'down'; override the default
interface by specifying an alternate interface with MONITORED_NETWORK=eth1, and override the default
units (bits) with NETWORK_UNITS=bytes, and override the default NETWORK_THRESHOLD=20 (kbps) in
$BYOBU_CONFIG_DIR/statusrc
notify_osd - Send on-screen notification messages to screen's notification buffer
processes - total number of processes running on the system; displayed in the lower bar in white text on
a dark yellow background with a trailing '&' indicating 'background processes'
reboot_required - symbol present if a reboot is required following a system update; displayed in the
lower bar white text on a blue background by the symbol '(R)'; additionally, reboot_required will print
'<F5>' in white text on a blue background, if Byobu requires you to reload your profile to affect some
changes; it will also detect if your system is currently in powernap(8) state and if so print '.zZ'.
release - OS/distribution name of the release running on the current system as reported by lsb_release(1)
or /etc/issue; displayed in the lower bar in bold black text toward the left on a grey background; you
may override the detected release with RELEASE=Whatever in $BYOBU_CONFIG_DIR/statusrc; you may also
abbreviate the release string to N characters by setting RELEASE_ABBREVIATED=N in
$BYOBU_CONFIG_DIR/statusrc
services - users can configure a list of services to monitor, define the SERVICES variable in
$BYOBU_CONFIG_DIR/statusrc, a whitespace separated of services, each service should include the init name
of the service, then a pipe, and then an abbreviated name or symbol to display when running (e.g.
SERVICES="ssh|ssh apache2|http"); displayed in the lower bar toward the center in cyan on a white
background
session - byobu session name (only supported in byobu-tmux(1)); displayed in the lower bar on the left in
underlined black text on a white background
swap - total swap space and total used as a percentage of the total available; displayed in the lower bar
toward the right in white text on a light green background with a trailing '%' sign
time - the system time in HH:MM:SS format (by default), or you can set this to any valid strftime(3) you
like in $BYOBU_CONFIG_DIR/datetime; displayed in the lower bar on the far right in the default text and
default background colors
time_binary - only for the hard core geek, the local system time in binary; requires UTF-8 support in a
VERY recent version of GNU Screen; displayed in the lower bar on the far right in the default text and
background colors
time_utc - the UTC system time in HH:MM format; displayed in the lower bar on the far right in dark text
on a light background
updates_available - the number of updates available on the system; displayed in the lower bar toward the
right in white text on a red background with a trailing '!' sign; if any updates are marked 'security
updates', then there will be a total of two trailing exclamation points, '!!'
uptime - the total system uptime since last boot; displayed in the lower bar toward the right in blue
text on a grey background
users - the number of remote users logged into the system via sshd, empty if 0 users; displayed in the
lower bar toward the right in red text on a grey background with a trailing '#' sign; set
USERS_DISTINCT=1 to instead count the number of distinct users logged into the system (rather than open
ssh sessions)
whoami - the name of the user who owns the screen session; displayed in the upper bar toward the far
right in bold black text on a grey background
wifi_quality - the connection rate and signal quality of the wifi connection; displayed in the lower bar
toward the right in black text on a cyan background; the connection rate is in 'Mb/s' and the signal
quality is as a percentage with a trailing '%'; override the default interface by specifying an alternate
interface with MONITORED_NETWORK=wlan0 in $BYOBU_CONFIG_DIR/statusrc
SESSIONS
Byobu name screen sessions "byobu", if unspecified. To hide sessions from byobu-select-session(1),
prepend a "." to the beginning of the session name, like:
byobu -S .hidden
WINDOWS
Each open window in the screen session is displayed in the upper bar toward the far left. These are
numbered, and include indicators as to activity in the window (see "activity" in screen(1) for symbol
definitions). The current active window is highlighted by inverting the background/text from the rest of
the window bar.
Users can create a list of windows to launch at startup in $BYOBU_CONFIG_DIR/windows. This file is the
same syntax as ~/.screenrc, each line specifying a window using the "screen" command, as described in
screen(1).
User can also launch Byobu with unique window sets. Users can store these as
$BYOBU_CONFIG_DIR/windows.[NAME], and launch Byobu with the environment variable BYOBU_WINDOWS.
For example:
$ cat $BYOBU_CONFIG_DIR/windows.ssh_sessions
screen -t localhost bash
screen -t aussie ssh root@aussie
screen -t beagle ssh root@beagle
screen -t collie ssh root@collie
$ BYOBU_WINDOWS=ssh_sessions byobu
UNITS OF MEASURE
byobu uses binary for capacity measurements of KB, MB, GB, and TB. This means multiples of 1024 rather
than multiples of 1000, in accordance with JEDEC Standard 100B.01 for disk and memory capacity
measurements. See:
* http://en.wikipedia.org/wiki/JEDEC_memory_standards
byobu uses decimal for measurements of network data transfer, meaning multiple of 1000, rather than 1024.
See:
* http://en.wikipedia.org/wiki/Data_rate_units
KEYBINDINGS
byobu keybindings can be user defined in /usr/share/byobu/keybindings/ (or within .screenrc if byobu-
export was used). The common key bindings are:
F2 - Create a new window
F3 - Move to previous window
F4 - Move to next window
F5 - Reload profile
F6 - Detach from this session
F7 - Enter copy/scrollback mode
F8 - Re-title a window
F9 - Configuration Menu
F12 - Lock this terminal
shift-F2 - Split the screen horizontally
ctrl-F2 - Split the screen vertically
shift-F3 - Shift the focus to the previous split region
shift-F4 - Shift the focus to the next split region
shift-F5 - Join all splits
ctrl-F6 - Remove this split
ctrl-F5 - Reconnect GPG and SSH sockets
shift-F6 - Detach, but do not logout
alt-pgup - Enter scrollback mode
alt-pgdn - Enter scrollback mode
Ctrl-a $ - show detailed status
Ctrl-a R - Reload profile
Ctrl-a ! - Toggle key bindings on and off
Ctrl-a k - Kill the current window
Ctrl-a ~ - Save the current window's scrollback buffer
SCROLLBACK, COPY, PASTE MODES
Each window in Byobu has up to 10,000 lines of scrollback history, which you can enter and navigate using
the alt-pgup and alt-pgdn keys. Exit this scrollback mode by hitting enter. You can also easily copy
and paste text from scrollback mode. To do so, enter scrollback using alt-pgup or alt-pgdn, press the
spacebar to start highlighting text, use up/down/left/right/pgup/pgdn to select the text, and press enter
to copy the text. You can then paste the text using alt-insert or ctrl-a-].
BUGS
For Byobu colors to work properly, older versions of GNU Screen require a 1-line patch to adjust
MAX_WINMSG_REND in screen.c. The change is in GNU Screen's upstream source control system as of
2010-01-26, but GNU Screen has not released a new upstream version in several years. You can disable
colors entirely by setting MONOCHROME=1 in $BYOBU_CONFIG_DIR/statusrc. For more information, see:
* http://savannah.gnu.org/bugs/?22146
PuTTY users have reported that the F2, F3, and F4 shortcut keys are not working properly. PuTTY sends
the same escape sequences as the linux console for F1-F4 by default. You can fix this problem in the
PuTTY config, Terminal -> Keyboard -> Function keys: Xterm R6. See: http://www.mail-archive.com/screen-
users@gnu.org/msg01525.html
PuTTY users should configure enable UTF-8 characters in order to fix status refresh issues. You can fix
this problem in the PuTTY configuration, Window -> Translation: select UTF-8.
PuTTY users should avoid resizing their window to one character tall, as this can sometimes crash byobu-
screen.
Apple Mac OSX terminal users have reported 'flashing text'. You can fix this in the advanced settings of
the terminal application, with 'Declare Terminal As: xterm-color'.
Apple Mac keyboard users may need to specify a vt100 terminal by adding this to your OSX profile, in
order to get Byobu's function keys and colors to work:
alias ssh='TERM=vt100 ssh'
Users of a non-UTF-8 locale (such as cs_CZ charset ISO-8859-2), may need to add "defutf8 off" to
~/.screenrc, if some characters are rendering as "?".
Users who customize their PS1 prompt need to put this setting in ~/.bashrc, rather than ~/.profile, in
order for it to work correctly with Byobu.
If you run byobu(1) under sudo(8), you must use the -H option, such that the user's $HOME directory
environment variable is set properly. Otherwise, byobu(1) will create a bunch of directories in the
$SUDO_USER's $HOME, but will be owned by root. To prevent this from happening, byobu(1) will simply
refuse to run if $USER does not own $HOME.
Byobu requires a suitable ulimit(3) values to run. If you get an error at startup saying, 'pipe: too
many open files', then check your ulimit -a values, as your "open files" or "max user processes" are too
low. In this case, you will probably need to run simple screen(1)
SEE ALSO
screen(1), byobu-config(1), byobu-export(1), byobu-status(1), byobu-status-detail(1), byobu-enable(1),
byobu-launch(1), byobu-select-backend(1), tmux(1)
http://byobu.co
AUTHOR
This manpage and the utility were written by Dustin Kirkland <kirkland@byobu.co> for Ubuntu systems (but
may be used by others). Permission is granted to copy, distribute and/or modify this document and the
utility under the terms of the GNU General Public License, Version 3 published by the Free Software
Foundation.
The complete text of the GNU General Public License can be found in /usr/share/common-licenses/GPL on
Debian/Ubuntu systems, or in /usr/share/doc/fedora-release-*/GPL on Fedora systems, or on the web at
http://www.gnu.org/licenses/gpl.txt.