Unix Trix

Ever been diagnosing a network and wanted to know how ping is getting somewhere? Adding -R (record routes) to your ping command will show you something like this –

 # ping -R 192.168.0.1
PING 192.168.0.1 (192.168.0.1): 56 data bytes
64 bytes from 192.168.0.1: icmp_seq=0 ttl=64 time=0.222 ms
RR:     192.168.0.1
testbox (192.168.5.1)

Not a bad list of “10 Linux Commands You’ve Never Used“. Obviously most of these are application to any nix variant, so are worth checking out.

My personal favourite tool –

 ldd, want to know which Linux thread library java is linked to?

# ldd /usr/java/jre1.5.0_11/bin/java
libpthread.so.0 => /lib/tls/libpthread.so.0 (0x00bd4000)
libdl.so.2 => /lib/libdl.so.2 (0x00b87000)
libc.so.6 => /lib/tls/libc.so.6 (0x00a5a000)
/lib/ld-linux.so.2 (0x00a3c000)

If your SysV (used by cache programs, and others) isn’t working inside your FreeBSD jail simply set “security.jail.sysvipc_allowed=1″ in /etc/sysctl.conf. Note that there are possible security implications with this.

pkg_add is a FreeBSD tool for installing packages, much like Linux’s apt-get and other tools. When you run it you can use the -r option to fetch a package, for example:

 pkg_add -v -r zip

When you do this, you’ll see it going off to download from one of the main FreeBSD servers, which can often be far away from you and a lot slower. If you’d like to download locally set the PACKAGEROOT environment variable to the server you’d like to use. For example:

export PACKAGEROOT=ftp://ftp.za.freebsd.org

“za” is the country code for South Africa. Most countries have local mirrors, and there are lists online. For example, “uk” or “au” would be for the UK or Australia.

Lifehacker has the link to an Ubuntu Tutorial on Installing Plugins for Gnome-Do the launcher. If you don’t know, Gnome-Do is a powerful application launcher, much like some of the apps available for Windows.

 … extend Gnome-Do’s powers to music management, Gmail, system functions, and other tasks, Ubuntu Tutorials has put together a simple guide to installing plug-ins for the launcher, a trick that’s not readily apparent for first-time users …

If your reading this you’re most likely a *nix user, and if you’re most likely a *nix user you most likely use MySQL. A big part of a speedy MySQL install is using the right queries, and going about analyzing them in the right way, so 20bits gives you: 10 tips for Optimizing MySQL Queries that don’t suck.