IP CIDR calculator
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IP Multicast address ranges
All multicast addresses can easily be recognized because they start with the bit pattern “1110”.
224.0.0.0 - 224.0.0.255 Well-known multicast addresses, control channels
224.0.1.0 - 238.255.255.255 Globally-scoped (Internet-wide) multicast addresses
239.0.0.0 - 239.255.255.255 Local multicast addresses
Special and private address ranges
Private address ranges are not routed on the Internet and can be freely allocated in any private network. NAT (network address translation) is required when connecting such a network to the Internet.
Private network addresses (RFC1597/RFC1918 addresses):
10.0.0.0 - 10.255.255.255 A 24-bit block, /8, class A network
172.16.0.0 - 172.31.255.255 A 20-bit block, /12, set of 16 contiguous class B network numbers
192.168.0.0 - 192.168.255.255 A 16-bit block, /16, set of 255 contiguous class C network numbers
Special addresses:
127.0.0.0 - 127.255.255.255 Special address range for the localhost. You can normally not use those addresses for anything else. 127.0.0.1 is generally assigned to the loopback device
0.0.0.0 _Special host address commonly reserved for the default route _
Overview of common subnets and masks
Mask Hosts Usable Netmask Hex Mask /30 4 2 255.255.255.252 fffffffc this is 1/64 of a Class C net /29 8 6 255.255.255.248 fffffff8 this is 1/32 of a Class C net /28 16 14 255.255.255.240 fffffff0 this is 1/16 of a Class C net /27 32 30 255.255.255.224 ffffffe0 this is 1/8 of a Class C net /26 64 62 255.255.255.192 ffffffc0 this is 1/4 of a Class C net /24 256 254 255.255.255.0 ffffff00 this is a Class C net /23 512 510 255.255.254.0 fffffe00 these are 2 Class C net /22 1024 1022 255.255.252.0 fffffc00 these are 4 Class C net /21 2048 2046 255.255.248.0 fffff800 these are 8 Class C net /20 4096 4094 255.255.240.0 fffff000 these are 16 Class C net /19 8192 8190 255.255.224.0 ffffe000 these are 32 Class C net /18 16384 16382 255.255.192.0 ffffc000 these are 64 Class C net /17 32768 32766 255.255.128.0 ffff8000 these are 128 Class C net /16 65536 65534 255.255.0.0 ffff0000 these are 256 Class C net = Class B net

screen and tmux
A comparison of the features (or more-so just a table of notes for accessing some of those features) for GNU screen and BSD-licensed tmux.
The formatting here is simple enough to understand (I would hope). ^ means ctrl+, so ^x is ctrl+x. M- means meta (generally left-alt or escape)+, so M-x is left-alt+x It should be noted that this is no where near a full feature-set of either group. This - being a cheat-sheet - is just to point out the most very basic features to get you on the road. Trust the developers and manpage writers more than me. This document is originally from 2009 when tmux was still new - since then both of these programs have had many updates and features added (not all of which have been dutifully noted here). |
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Action | tmux | screen |
start a new session | tmux OR tmux new OR tmux new-session |
screen |
re-attach a detached session | tmux attach OR tmux attach-session |
screen-r |
re-attach an attached session (detaching it from elsewhere) | tmux attach -d OR tmux attach-session -d |
screen -dr |
re-attach an attached session (keeping it attached elsewhere) | tmux attach OR tmux attach-session |
screen -x |
detach from currently attached session | ^b d OR ^b :detach |
^a ^d OR ^a :detach |
rename-window to newname | ^b , <newname> OR ^b :rename-window <newn> |
^a A <newname> |
list windows | ^b w | ^a w |
list windows in chooseable menu | ^a " | |
go to window # | ^b # | ^a # |
go to last-active window | ^b l | ^a ^a |
go to next window | ^b n | ^a n |
go to previous window | ^b p | ^a p |
see keybindings | ^b ? | ^a ? |
list sessions | ^b s OR tmux ls OR tmux list-sessions |
screen -ls |
toggle visual bell | ^a ^g | |
create another window | ^b c | ^a c |
exit current shell/window | ^d | ^d |
split window/pane horizontally | ^b " | ^a S |
split window/pane vertically | ^b % | ^a | |
switch to other pane | ^b o | ^a <tab> |
kill the current pane | ^b x OR (logout/^D) | |
collapse the current pane/split (but leave processes running) | ^a X | |
cycle location of panes | ^b ^o | |
swap current pane with previous | ^b { | |
swap current pane with next | ^b } | |
show time | ^b t | |
show numeric values of panes | ^b q | |
toggle zoom-state of current pane (maximize/return current pane) | ^b z | |
break the current pane out of its window (to form new window) | ^b ! | |
re-arrange current panels within same window (different layouts) | ^b [space] | |
Kill the current window (and all panes within) | ^b killw [target-window] |