{{ parent page="HomePage" }} ==== Linux Area ==== [[LinuxTerminal Terminal ]] [[LinuxKernel Kernel ]] [[LinuxBoot Boot]] [[LinuxFilesystem Filesystem ]] [[LinuxSamba Samba ]] [[LinuxSecurity Security ]] [[LinuxXwin XWindows ]] [[LinuxUSB USB ]] [[LinuxLanguage Language ]] [[LinuxPrinting Printing ]] [[LinuxInstall Installation ]] [[LinuxSingle Grub single user mode]] [[LinuxFonts Fonts ]] [[LinuxRPM RPM ]] [[LinuxMake Compilation ]] [[LinuxRsync Rsync ]] [[LinuxSudo Sudo]] [[LinuxSNMP SNMP]] [[LinuxSound Sound with OSS]] [[LinuxNICBonding NIC Bonding]] [[LinuxStrace strace]] [[LinuxKickStart KickStart]] [[LinuxDVDWriting DVDWriting]] [[LinuxCDWriting CDWriting]] [[LinuxLTSP LTSP]] [[LinuxCompile Compile]] [[LinuxWine Wine]] [[LinuxProcfs ProcFS]] [[LinuxBenchmark Benchmark]] [[LinuxMultiMedia Multimedia]] [[LinuxNetTuning NetTuning]] [[LinuxWireless WirelessNetworking]] [[LinuxSensors Sensors]] [[LinuxRPMRepository Custom Repo]] [[LinuxMouse Mouse]] [[LinuxPackage Package]] [[LinuxNFS NFS]] [[LinuxSyslog Syslog]] [[LinuxSessionReplay Record and replay session]] [[LinuxHardening OS Hardening]] [[LinuxCompression Compression]] [[LinuxConsole Console]] [[LinuxCrashDump Crashdump]] ----- === Distribution specific=== [[LinuxUbuntu Ubuntu]] [[LinuxDebian Debian]] [[LinuxRedhat Redhat]] [[LinuxFedora Fedora]] [[LinuxCentos CentOS]] [[LinuxSuse SuSe]] [[LinuxKnoppix Knoppix]] ===Networking tweaks=== ifconfig eth0 mtu 9000 txqueuelen 10000 modprobe tcp_illinois net.ipv4.tcp_congestion_control = illinois ===Adding additional repository to yum=== Repositories: ~[[http://dag.wieers.com/rpm/FAQ.php#B2 DAG]] ~[[http://gstreamer.freedesktop.org/download/fedora5.html GStreamer]] ===More on YUM=== Install yum-skip-broken such that you can add --skip-broken switch to yum. Find yum-skip-broken rpm from your favorite rpm search site. ===Configure options I used for various software=== [[ConfigureOptions Configure]] ===ipcs=== The ipcs utility lists the opened semaphores. %% ipcs %% To remove semaphores owned by the user "www" %% ipcs|grep www|awk '{print $2}'|xargs -n 1 ipcrm -s %% ===Fast way to add swap === Create a 1G swap file %% dd of=/.swap01 bs=1k count=0 seek=1M mkswap /.swap01 swapon /.swap01 %% === rsync & ssh === %%(bash) rsync -avvxz -e ssh source_file root@1.2.3.4:/dest/dir %% ===syn attack=== Add more buffer to your kernel and reduce syn retries. It seems to be somewhat effective towards syn attacks when remote servers try to reduce the tcp window to 0 on the initial handshake. %% net.ipv4.tcp_synack_retries = 3 net.ipv4.tcp_syn_retries = 3 net.ipv4.tcp_max_syn_backlog = 4096 %% === DST fix for Redhat 9 === %% 1. Downloaded the tzdata2007c.tar.gz file from /pub/ at elsie.nci.nih.gov. 2. Extracted the tar.gz file: 3. Used zic to create the new zoneinfo file: # zic -d zoneinfo northamerica # cd zoneinfo # cp -r * /usr/share/zoneinfo/ 3. Typed zdump -v `echo $TZ` | grep 2010 to confirm that the DST patch had been applied. Results: %% US/Eastern Wed Nov 3 04:20:50 2010 UTC = Wed Nov 3 00:20:50 2010 EDT isdst=1 US/Eastern Sun Mar 14 06:59:59 2010 UTC = Sun Mar 14 01:59:59 2010 EST isdst=0 US/Eastern Sun Mar 14 07:00:00 2010 UTC = Sun Mar 14 03:00:00 2010 EDT isdst=1 US/Eastern Sun Nov 7 05:59:59 2010 UTC = Sun Nov 7 01:59:59 2010 EDT isdst=1 US/Eastern Sun Nov 7 06:00:00 2010 UTC = Sun Nov 7 01:00:00 2010 EST isdst=0 %% More information on zdump %% zdump -v /etc/localtime EST5EDT | grep 2007 %% is what you would use for the U.S. Eastern time zone. If you're in the Central time zone, use CST6CDT; in the Mountain time zone use MST7MDT; and in the Pacific time zone, use PST8PDT. If your system is set up properly, it will return a display that starts with two lines containing "Sun Mar 11". If, instead, you see a pair of lines with "Sun Apr 1" within them, you'll need to do a manual update. === Static routes === On Redhat, create a file /etc/sysconfig/network-scripts/route-eth0 with the following content. Note: /etc/sysconfig/static-route no longer works. %% 192.168.7.0/24 via 192.168.1.254 %% Redhat says it should be this. http://kbase.redhat.com/faq/FAQ_45_9670.shtm %% GATEWAY0=192.168.1.1 NETMASK0=255.255.255.0 ADDRESS0=10.10.10.0 GATEWAY1=192.168.1.1 NETMASK1=255.255.255.0 ADDRESS1=20.20.20.2 %% On FreeBSD, add a static route to network in rc.conf: %% static_routes="rsite1" route_rsite1="-net 192.168.7.0 192.168.1.254 255.255.255.0" %% ===MTU size=== Experiment with the ping -s option %% ping -s 9000 1.2.3.4 %% ===preload=== http://www.techthrob.com/tech/preload.php ===max arguments=== If you run into argument list too long, the following probably won't help you. Pipe your output to xargs. %% # getconf ARG_MAX 2097152 # sysctl kern.argmax kern.argmax=2097152 %% ===find and xargs=== These are the tools that most linux administartors will be familiar with. Here are some interesting options: ""
tooloptionmeaningdefault
xargs -n 99number of arguments to pass at a time na
xargs -P 99 number of processes to spawn 1
"" ===Capturing mouse / keyboard event under X=== use xev === Create ISO image === mkisofs -l -J -L -r -o output.iso file_list ===Schedule task with at=== %% atq - list at jobs at -c - cat job at 17:00 friday - schedule job at that time %% === Plesk === It does not belong to anywhere so I'll just put it here. http://rackerhacker.com ==zramswap== http://www.webupd8.org/2011/10/increased-performance-in-linux-with.html