Some are new programs for old jobs: programs like ls(1), cat(1), and who(1) have familiar names and functions but are new, simpler implementations. Who, for example, is a shell script, while ps is just 163 lines of C code.
Some commands are essentially the same as their UNIX ancestors: awk(1), troff(1), and others have been converted to ANSI C and extended to handle Unicode, but are still the familiar tools.
Some are entirely new programs for old niches: the shell rc(1), text editors acme(1) and sam(1), debuggers acid(1) and db(1), and others displace the better-known UNIX tools with similar jobs.
Compatibility was not a requirement for the system. Where the old commands or notation seemed good enough, we kept them. When they didn't, we replaced them.
The following list of some UNIX commands, files, and shell terminology, which you can emulate in a Plan 9 system:
UNIX Plan 9 from Bell Labs `command` `{ command } .profile $home/lib/profile ^C (Ctrl+C) DEL key -- doesn't work without rio(4) though. ~ $home /usr/$user/ ~username /usr/username "$@" $* 1>&2 >[2=1] apropos lookman(1) at specific-time while (! ~ (`{ date }) (specific-time)); commands cc one of ones in 0c(1) followed by the same of 0l(1) pcc(1) for Standard C/POSIX programs cp -r /foo/ /bar/ mkdir /bar/foo/ && dircp /foo/ /bar/foo/ crontab -e sam /cron/$user/cron curl http://foo/bar wget http://foo/bar hget http://foo/bar > bar (progress bar, -t for ascii) hget -v -o bar http://foo/bar |[2] aux/statusbar [-t] 'downloading' cut awk -F ... apt-get dist-upgrade rpm -Ua yum -c update /usr/glenda/bin/rc/pull apt-get install rpm -i package yum -c install package 9fs sources ; cd /n/sources/ /n/sources/contrib/fgb/root/rc/bin/contrib/install fgb/contrib ; contrib/install $who/$what df disk/kfscmd check echo fsys all df | con -l /srv/fscons df in fossilcons(8) ee emacs jim joe nano pico vi xedit sam acme expr hoc -e find du -a | grep pattern grep pattern `{du -a root} -name du -a root | grep name pattern in a file grep -n pattern `{du -a root | awk '{print $2}'} -exec cp '{}' x ';' cp `{ du -a | grep pattern } x fsck echo fsys all check fix | con -l /srv/fscons if running venti, for a thorough fix: echo fsys all check fix venti snapshot | con -l /srv/fscons ftp ftpfs host.domain (Remote files apear in /n/ftp). ftpd aux/listen ftp getopt getflags(8) groff -l troff | lp grops dpost - see troff(1) head sed 10q hwclock cat '#r/rtc' aux/timesync id echo $user cat /dev/user grep `{cat /dev/user} /adm/users grep $user /adm/users iostat iostats(4) ifconfig(IP address) cat /net/ndb ifconfig ip/ipconfig ether /net/ether0 add 192.168.1.32 ip/ipconfig # let dhcp do it kill pid stop processname | rc echo stop > /proc/pid/ctl (in both cases, switch stop with start to get it back) kill -9 pid kill -KILL pid slay processname | rc echo kill > /proc/pid/ctl ld one of the ones in 0l(1) ls lc -F lspci pci -v make mk (not exactly the same) if necessary, use make in ape/psh man -k lookman(1) less more p mount [-p flag] bind(1) unmount(1) 9fs(1) srv(1) import(4) exportfs(4) -p ns(1) mount /dev/fd0 /mnt a: ; cd /n/a: mount /dev/acd0 /mnt 9660srv mkdir /n/9660 mount /srv/9660 /n/9660 /dev/sdD0/data netcat -l aux/listen1 -t tcp!*!$port command netstat [-r flag] netstat(1) -r cat /net/iproute nfsstat iostats(4) nslookup ndb/dnsquery passwd auth/changeuser username (first time) passwd (subsequent times) paste [FILE] ... pr -m [FILE] ... PATH=$PATH:... bind -a directory /bin ping ip/ping pkginfo wrap(8) reboot fshalt -r (note that there is a reboot command, but it doesn't call fshalt) rmdir rm(1) With contents inside: rm -r dir sh rc(1) if necessary, ape/psh shutdown fshalt(8) echo reboot > /dev/reboot echo panic > /dev/reboot snoop snoopy(8) source . startx launch (Andrew Project) mux (Blit's wm) rio (replaces 8½ and help) tar xzf file.tgz tar xf file.tgz tcpdump snoopy(8) traceroute ip/traceroute tree du $* | awk '{print $2}' | sort | sed 's/[^\/]+\// /g' ufs{dump|restore} yesterday(1) history(1) fs(4) vigr vipw [Adding a new user] vlock http://mirtchovski.com/lanlp9/rlock (specify password at invocation) vmstat stats(1) cat /dev/sysstat cat /dev/swap which whatis xbiff faces xclock clock games/catclock faces xditview troff | page troff | proof xload stats -l xlock /n/sources/contrib/steve/conslock (authenticates against authentication server) xlogo window 'hget http://plan9.bell-labs.com/plan9/img/plan9bunnysmblack.jpg | page' xman cat man -t cat | page xv file.jpg page file.jpg xwininfo winwatch yes while() { echo y } yes arg while() { echo arg }