Specials
The following is a special collection of freeware tools for system administration written in Perl. They cover advanced topics for the experienced admin, and are a valuable addition to a senior admin's collection or those wishing to be a senior admin. Most are related to performance or fault prevention.
Note: These are unsupported freeware programs and have nothing to do with the respective operating system vendors. Use at your own risk.
Operating Systems
Many of these require Perl and were developed on Unix, and many of these run fine on Linux. A few are specific to Unix. Later tools, after the Linux Internals diagram, were developed for Linux.
Screenshots and Downloads
The following are short demonstrations for each of the programs with links to download the code.
baud Run commands safley at their native baud, eg 2400, 9600. Commands are often run over high speed ssh or telnet sessions, causing Command Fault Heat State Exception (CFHSE) errors due to overbauding. This program helps prevent such faults. Full example here.
brendan:/etc/ftpd> baud -9600 ls -l total 14 -rw-r--r-- 1 root sys 1249 Jun 4 2002 ftpaccess -rw-r--r-- 1 root sys 551 Jun 4 2002 ftpconversions -rw-r--r-- 1 root sys 104 Jun 4 2002 ftpgroups -rw-r--r-- 1 root sys 108 Jun 4 2002 ftphosts -rw-r--r-- 1 root sys 114 Jun 4 2002 ftpservers -rw-r--r-- 1 root sys 180 Jun 10 2002 ftpusers
cdrewind Rewind CDROMs before ejection. This should be performed before every ejection, otherwise discs can remain positioned incorrectly or can leave tracks behind in the drives. Full example here.
$ cdrewind -v /vol/dev/aliases/cdrom0 CDROM rewound successfully. $ eject cdrom
psss Process Status with Star Sign, an improved ps version that inserts a field to display the starsign of the process. See the Process Star Sign Chart for starsign characteristics. Full example here.
$ psss
UID PID STIME STARSIGN %CPU %MEM COMMAND
0 0 Apr_06 aries 0.0 0.0 sched
0 1 Apr_06 aries 0.0 0.1 /etc/init -
0 2 Apr_06 aries 0.0 0.0 pageout
0 3 Apr_06 aries 0.2 0.0 fsflush
0 434 Apr_06 aries 0.0 0.1 /usr/lib/saf/sac -t 300
[...]
lsss ls with StarSign, an improved ls command that inserts a field to display the starsign of each file. Full example here.
$ lsss /etc/default total 49 -r-xr-xr-x 1 root 12 gemini Jun 4 2002 cron -r--r--r-- 1 root 204 gemini Jun 4 2002 devfsadm -r--r--r-- 1 root 3388 gemini Jun 4 2002 dhcpagent -r--r--r-- 1 root 10 gemini Jun 4 2002 fs -r--r--r-- 1 root 719 aquarius Jan 23 2004 inetd -r--r--r-- 1 root 379 gemini Jun 4 2002 inetinit -r-xr-xr-x 1 root 638 gemini Jun 4 2002 init -r--r--r-- 1 root 1182 virgo Sep 15 2002 kbd [...]
bottom This is the opposite of top, it displays processes that are using the least CPU. It is the companion to the "prstat" command. Full example here.
$ bottom
PID USERNAME SIZE RSS STATE PRI NICE TIME CPU PROCESS/NLWP
505 brendan 2124K 924K sleep 59 0 00:00 0.0% fbconsol/1
511 brendan 2552K 832K sleep 59 0 00:00 0.0% speckeys/1
347 root 1680K 608K sleep 59 0 00:00 0.0% smcboot/1
208 root 1680K 760K sleep 59 0 00:00 0.0% sac/1
225 root 1788K 812K sleep 59 0 00:00 0.0% ttymon/1
462 root 2124K 880K sleep 59 0 00:00 0.0% fbconsol/1
430 root 2716K 1188K sleep 59 0 00:02 0.0% vold/3
604 brendan 2508K 1536K sleep 59 0 00:00 0.0% bash/1
601 brendan 2508K 1448K sleep 59 0 00:00 0.0% bash/1
108 root 1228K 536K sleep 59 0 00:00 0.0% powerd/2
488 brendan 1176K 644K sleep 59 0 00:00 0.0% Xsession/1
582 brendan 7508K 1936K sleep 49 0 00:00 0.0% dtfile/1
18640 brendan 1160K 848K sleep 59 0 00:00 0.0% more/1
84 root 2584K 740K sleep 59 0 00:00 0.0% picld/4
587 brendan 1160K 624K sleep 59 0 00:00 0.0% sdtvolch/1
560 brendan 2136K 724K sleep 59 0 00:00 0.0% dsdm/1
598 brendan 2508K 1488K run 58 0 00:01 0.0% bash/1
200 daemon 2040K 816K sleep 60 -20 00:00 0.0% lockd/2
460 root 6540K 1560K sleep 59 0 00:00 0.0% snmpd/1
18857 root 948K 656K sleep 49 0 00:00 0.0% sleep/1
193 daemon 2276K 800K sleep 59 0 00:00 0.0% rpcbind/1
7 root 11M 2056K sleep 59 0 00:02 0.0% svc.star/12
ged.jar GUI-ed. A Java/Swing GUI front-end for the "ed" line editor. This enhances the classic "ed" editor by wrapping it in an easy to use GUI. The GUI provides tunable options such as sound effects, themes, and has an awe-inspiring monochrome splash screen. This runs on any OS with Java 1.5 and a valid "/usr/bin/ed". src.
Solaris/Linux:
$ ./ged.jar /etc/passwd
OS X:
$ sudo ln -s /bin/ed /usr/bin/ed $ java -jar ged.jar /etc/passwd
3rot13 Triple ROT13 - a new heavyweight encryption algorithm. This is a symmetric stateless keyless cypher that outperforms other modern encryption algorithms on speed. Full example. A newer version, nrot13 allows the number of ROT13 cycles to be customised; however due to export regulations cycles greater than 1024 should not be used.
$ 3rot13 -e < /etc/release > release.3rot13
$
$ cat release.3rot13
Fbynevf 9 f9_58fujcy3 FCNEP
Pbclevtug 2002 Fha Zvpebflfgrzf, Vap. Nyy Evtugf Erfreirq.
Hfr vf fhowrpg gb yvprafr grezf.
Nffrzoyrq 15 Ncevy 2002
$
gwhiz GWhiz. This will whiz files or commands, making them easier to read so that you do not miss important details. Full example.
$ gwhiz /etc/release
SOLARIS 9 S9_58SHWPL3 SPARC!!!
COPYRIGHT 2002 SUN MICROSYSTEMS, INC. ALL RIGHTS RESERVED.!!!
USE IS SUBJECT TO LICENSE TERMS.!!!
ASSEMBLED 15 APRIL 2002!!!
$ df -k | gwhiz
FILESYSTEM KBYTES USED AVAIL CAPACITY MOUNTED ON!!!
/DEV/DSK/C0T0D0S1 246463 101675 142324 42% /!!!
/DEV/DSK/C0T0D0S3 4628486 2057182 2525020 45% /USR!!!
/PROC 0 0 0 0% /PROC!!!
MNTTAB 0 0 0 0% /ETC/MNTTAB!!!
FD 0 0 0 0% /DEV/FD!!!
/DEV/DSK/C0T0D0S5 492422 229179 263243 47% /VAR!!!
SWAP 454088 120 453968 1% /VAR/RUN!!!
SWAP 476424 22456 453968 5% /TMP!!!
/DEV/DSK/C0T0D0S7 246463 48333 173484 22% /DATA!!!
/DEV/DSK/C0T0D0S4 2052750 1304271 727952 65% /OPT!!!
/DEV/DSK/C0T2D0S1 18530217 3682119 14662796 21% /EXPORT/HOME!!!
$ uptime | gwhiz
8:47PM UP 286 DAY(S), 6:50, 3 USERS, LOAD AVERAGE: 0.00, 0.01, 0.02!!!
If your terminal supports colour, gwhiz can highlight in colour using the "-c" option. Here we also use "-v" for verbose,
$ df -k | gwhiz -cv FILESYSTEM KBYTES USED AVAIL CAPACITY MOUNTED ON Wow!!! /DEV/DSK/C0T0D0S1 246463 101675 142324 42% / Wow!!! /DEV/DSK/C0T0D0S3 4628486 2057185 2525017 45% /USR!!! /PROC 0 0 0 0% /PROC Fairdinkum!!! MNTTAB 0 0 0 0% /ETC/MNTTAB!!! FD 0 0 0 0% /DEV/FD Crikey!!! /DEV/DSK/C0T0D0S5 492422 229335 263087 47% /VAR!!! SWAP 444472 120 444352 1% /VAR/RUN!!! SWAP 466824 22472 444352 5% /TMP!!! /DEV/DSK/C0T0D0S7 246463 48333 173484 22% /DATA!!! /DEV/DSK/C0T0D0S4 2052750 1305957 726266 65% /OPT Cor Blimey!!! /DEV/DSK/C0T2D0S1 18530217 3685344 14659571 21% /EXPORT/HOME Gee Whiz!!!
l33t converts formal and confusing text into easily understandable l33t-speak. In the example below we show an original file, a l33t output, and a l33t output with all (-a) options. Full example.
$ cat /etc/release
Solaris 9 s9_58shwpl3 SPARC
Copyright 2002 Sun Microsystems, Inc. All Rights Reserved.
Use is subject to license terms.
Assembled 15 April 2002
$ l33t /etc/release
S0lari5 9 s9_58ZhWpL3 zpaRc!!!1
copyrIghT 2002 sun miCr0$y5T3mZ, inc. a1l riGH75 r3SERV3D.!!!!1
use Is 5uBj3c7 To lIC3ns3 7eRms.!!!11!!1ONE!
a$$emb1ed 15 APri1 2002!!!!
$ l33t -a /etc/release
S()lAR1s 9 $9_58ShwPL3 Sp@rC!!!!!! d00d
cOPyRIgh+ 2002 SuN micROsYsT3mz, 1NC. aLL R1gHTz Re53|2V3d.!!!!
use I5 $Ubj3C+ TO 1ic3NSE T3rM5.!!!
aS5eMB1ed 15 ApRIl 2002!!!!!! w00t!
turbo Toggle the turbo button. This is for servers that lack the physical turbo button that is used to double the CPU speed. You may be shocked to find that some of your servers have been running with turbo switched off all this time. Full example here.
# turbo
TURBO is now on
#
# cat -n /etc/turbo.conf
1 #
2 # turbo.conf
3 #
4 # Configuration parameters for turbo.
5 # Do NOT edit this file by hand -- use turbo(1m) instead.
6 #
7 TURBO=on
#
maybe /usr/bin/maybe. A companion to /usr/bin/true and /usr/bin/false. Full example here.
$ if maybe; then echo yes; fi $ if maybe; then echo yes; fi yes $
icmpcharger ICMP driver trickle charger. This trickle charges the ICMP driver by sending a series of echo reply packets to localhost at regular intervals. This prevents a common fault where the batteries in the kernel's ICMP driver become depleted, causing high latency or dropped packets. This script serves as a precaution against driver failure.
# icmpcharger & [1] 21620 # ICMP trickle charger: once per 111 secs... #
xmanagerstat A sophisticated system status tool with blinking lights. This provides a view of the server thinking in real time, a technique that was popular in the days of mainframe computers and is equally useful today.
$ xmanagerstat &
onstat Server on status. This program tells you if your server is switched on. There is also a C version, onstat.c. Full example here.
$ onstat Server is ON.
osstat OS version status. This program provides a convenient way to determine if your OS is upgraded, rebooted, reinstalled or BFU'd while you are using it. Full example here.
$ osstat 1
TIME OS_Ver u/s r/s i/s b/s
16:51:14 SunOS_5.11 0.0 0.0 0.0 0.0
16:51:15 SunOS_5.11 0.0 0.0 0.0 0.0
16:51:16 SunOS_5.11 0.0 0.0 0.0 0.0
16:51:17 SunOS_5.11 0.0 0.0 0.0 0.0
16:51:18 SunOS_5.11 0.0 0.0 0.0 0.0
^C
[...]
ishadm Information Super Highway Administration. This checks and enables network routes to the Information Super Highway to ensure maximum Internet performance. Full example here.
# ishadm -e add host information-super-highway: gateway 127.0.0.1 Information-Super-Highway is now ON. # # netstat -r Routing Table: IPv4 Destination Gateway Flags Ref Use Interface -------------------- -------------------- ----- ----- ------ --------- information-super-highway localhost UH 1 0 lo0 192.168.1.0 jupiter U 1 927 rtls0 default mars UG 1 0 rtls0 localhost localhost UH 4 91 lo0 #
bnull.c This is a block device version of /dev/null. It has been written to obey the Solaris 10 DDI. Full example.
# find /etc > /dev/null # find /etc > /dev/bnull # # ls -lL /dev/null crw-rw-rw- 1 root sys 13, 2 Nov 27 15:00 /dev/null # # ls -lL /dev/bnull brw-rw-rw- 1 root sys 181, 0 Nov 27 15:00 /dev/bnull #
notrandom.c This Solaris 10 device driver provides /dev/notrandom, which provides fast and reliable not random numbers. Full example.
# od -vc /dev/random | head -5 0000000 + n 253 026 - 020 210 R 321 324 V Q ? 033 312 ? 0000020 U 360 020 364 P 267 312 313 \b 204 = 251 262 267 244 @ 0000040 223 035 377 362 S , 332 217 330 201 261 240 031 216 \ 2 0000060 A 5 336 326 335 177 304 203 Q U 357 Y 365 346 327 246 0000100 304 325 026 240 344 035 S = r 031 311 6 225 320 302 242 # # od -vc /dev/notrandom | head -5 0000000 007 007 007 007 007 007 007 007 007 007 007 007 007 007 007 007 0000020 007 007 007 007 007 007 007 007 007 007 007 007 007 007 007 007 0000040 007 007 007 007 007 007 007 007 007 007 007 007 007 007 007 007 0000060 007 007 007 007 007 007 007 007 007 007 007 007 007 007 007 007 0000100 007 007 007 007 007 007 007 007 007 007 007 007 007 007 007 007 #
wumpus.c This is an mdb loadable module that provides a new dcmd, "::wumpus" that plays the classic game of Hunt the Wumpus. This is based on a clone of the original BASIC game. Full example here.
# mdb > ::load wumpus > ::wumpus INSTRUCTIONS (Y-N) ?N HUNT THE WUMPUS I SMELL A WUMPUS! BATS NEARBY! YOU ARE IN ROOM 17 TUNNELS LEAD TO 7 16 18 SHOOT OR MOVE (S-M) ?
music.xml Background Music Service for Solaris 10's SMF. This plays background computer music in a constant loop, making your server appear more important and high-tech. Full example here.
# svcadm enable music # svcs music STATE STIME FMRI online 18:40:59 svc:/site/music:default #
typewriter-0.75.tar.gz These are DTrace scripts that make your console keyboard sound like a mechanical keyboard, including the "ping-whoosh" sound when you hit enter. This is helpful if you have no feeling in your hands and you'd like to know when they are hitting keys. Or, if you are raising several kittens in the server room, this can alert you if they jump up on the keyboards.
# ./ultra5.d & [1] 7660 typewriter.d running for the console keyboard. #
ltzip Compress text files using a lossy text compression algorithm. Not only is the byte count reduced, but the bytes themselves are smaller bytes - and weigh less when stored on disk. Decompression to the original is not possible, however an ltunzip command exists for lossy decompression. Full example here.
$ ltzip -v release
Read : release 236 bytes
Created: release.ltz 122 bytes
Reduced: 48.31%
$
$ cat release
Solaris 9 s9_58shwpl3 SPARC
Copyright 2002 Sun Microsystems, Inc. All Rights Reserved.
Use is subject to license terms.
Assembled 15 April 2002
$ cat release.ltz
solaris9s9_58shwpl3sparc
copyright22sunmicrosystems,inc.allrightsreserved.
useissubjecttolicenseterms.
assembled15april22
$
$ ltunzip release.ltz
$ cat release.ltz.un
solARiS 9 s9 _58 shwpL3 spaR C
Co0P y r ight2 2sunm I c r OSYstemS ;i Nc:ALlr iGHt sr ese 0rved:
Us eisSubJect T o lic ensEt eRms:
ASsemb LeD15Ap ri l22
mkzombie.c This program creates one or more zombies and a daemon their leader. It can be used to replenish system zombies, or to feed the init monster. Full example here.
$ ./mkzombie 10
[1]+ Stopped ./mkzombie 10
$ ptree $$
402 /usr/dt/bin/dtlogin -daemon
461 /usr/dt/bin/dtlogin -daemon
488 /bin/ksh /usr/dt/bin/Xsession
558 /usr/dt/bin/sdt_shell -c unset DT; DISPLAY=:0;
561 -bash -c unset DT; DISPLAY=:0; /usr/dt/bin/d
574 /usr/dt/bin/dtsession
584 /usr/dt/bin/dtterm -session dthiaONe
598 /bin/bash
15904 ./mkzombie 10
15914 <defunct>
15913 <defunct>
15912 <defunct>
15911 <defunct>
15910 <defunct>
15909 <defunct>
15908 <defunct>
15907 <defunct>
15906 <defunct>
15905 <defunct>
15915 ptree 598
pam_happy_hour.c PAM happy hour module. This creates a happy hour on Solaris during which passwords aren't required, any will do. Full example here.
$ telnet jupiter Trying 192.168.1.15... Connected to jupiter. Escape character is '^]'. Jupiter. Authorized users only. login: fred Password: Welcome to happy hour! Last login: Sun Mar 6 22:31:51 from localhost Sun Microsystems Inc. SunOS 5.10 s10_63 May 2004 $
crypt_3rot13.c this is a password encryption library for Solaris 9, that allows the system to use the 3ROT13 (Triple-ROT13) algorithm for /etc/shadow passwords. Full example and Makefile here.
# passwd fred New Password:Re-enter new Password: passwd: password successfully changed for fred # # grep fred /etc/shadow fred:$3rot13$serq123:12856::::::
jecho Java version of echo. This obeys the POSIX 1003.1, 2004 standard. It provides a standard version of echo to run on all systems rather than depending on quirky shell builtins. Full example here.
$ java jecho Hello World Hello World
rshutdown rough shutdown, shutdown in roughly 5 minutes or so. This program uses the same countdown timer as many major railway networks throughout the world, including Sydney's CityRail. Full example here.
# rshutdown -N Shutdown started. Thu Dec 2 18:09:22 EST 2004 The system mars will be shutdown in 5 minutes The system mars will be shutdown in 4 minutes The system mars will be shutdown in 3 minutes The system mars will be shutdown in 2 minutes The system mars will be shutdown in 1 minute The system mars will be shutdown in 2 minutes The system mars will be shutdown in 1 minute THE SYSTEM mars IS BEING SHUT DOWN NOW ! ! !
allslow This program prevents greedy CPU-bound processes consuming so much CPU, by creating a DTrace program that is even greedier. It slows down every process on the system to about a tenth of their usual speed. Full example here.
# allslow allslow running... ^C Wasted CPU time 90% #
Linux Kernel Internals This is a diagram showing Linux kernel internals (from my 2014 SCaLE12x talk):
c64banner.sh Have you ever ran commands before the computer was ready for them? Your commands may become lost in a buffer hole, from which no bytes can escape. Imagine running "cd /tmp/1" then "rm -rf *", and it lost the first command but ran the second! With this dynamic motd, your computer announces in shouting-robot-speak when it is "READY" for your commands. The script has install instructions for Ubuntu Yakkity.
$ ssh [email protected] **** INTEL(R) XEON(R) CPU E5-2680 V2 @ 2.80GHZ **** 15401664K RAM SYSTEM 8988049408 BASIC BYTES FREE READY. root@ubuntu1610:~>