Disable IPv6 in opensuse

/etc/sysctl.conf

net.ipv6.conf.all.disable_ipv6 = 1

Writing files as root in vim

I do this at least once a day; open a file in vim, make changes, then get reminded that I didn't do it using sudo.

simple one-liner fixes this.

:w !sudo tee %

Thanks to http://www.cyberciti.biz/faq/vim-vi-text-editor-save-file-without-root-permission/ for that one.

using a remote machine as a proxy with SSH

This is such a useful feature of SSH that I wish I had know about before now.

When working remotely from an insecure location, or when only the remote location is trusted by another host, e.g for a firewall login or viewing intranet pages you only have access to from a certain machine; you can use a remote machine as a SOCKS proxy straight out of the box.

e.g. on the localmachine, run:

ssh -fND 1234 username@yourremotemachine

This will create a SOCKS proxy on localhost port 1234

-f flag tells the shell to fork and run in the background

-N Leaves no login shell

-D 1234 sets up a SOCKS proxy via port 1234 on the localhost

On the local machine you can then set the browser to use the SOCKS 5 proxy on localhost port 1234

diff files across servers

Here's another really handy one liner for diff-ing files across servers using process substitution. This seems to work in zsh and bash.

diff /a/file/ <(ssh anotherserver 'cat /a/file/')

Finding the most recently modified files with find

I recently needed to check that no files had been modified since I last made an archive of a certain directory. Here's a good one for geting a list of files by last modified date, newest at the top.

find . -type f -printf "%TY-%Tm-%Td %TT %pn\n" | sort -r | less

ctrl-a and ctrl-b not working in tmux on RHEL 5.5

Rather than moving to the beginning of a line and the end of a line, ctrl-a and ctrl-b were just print ^A and ^B to the screen. Not sure why, I don't really have time to investigate, but this seems to fix the issue when run within the tmux session.

set -o emacs

MySQL Grants grant and revoke

I'm not really a fan of MySQL but here is a simple problem I always forget the syntax for which is really a SQL issue.

An installation of MediaWiki has an update script which requires the DROP privilege on the database, so I wanted to add the DROP privilege, run the update script and revoke the DROP privilege again.

Here's how:

mysql> show grants for 'username'@'host';
mysql> grant drop on adatabase.* to 'username'@'host';
mysql> revoke drop on adatabase.* from 'username'@'host';

Job's a good-un!