Recently, I’ve been trying to setup dovecot with postfix on a server. While attempting to get kerberos/ldap authentication working, I’ve ran into the following error:

dovecot: Feb 22 22:43:02 Error: IMAP(leo): fcntl() failed with file /home/leo/Maildir/dovecot.index.log: No locks available
dovecot: Feb 22 22:43:02 Error: IMAP(leo): mail_index_wait_lock_fd() failed with file /home/leo/Maildir/dovecot.index.log: No locks available

The /home directory is a automounted NFS share from a remote server. To resolve this issue, ensure that nfslock is running on both the server and client machine.

Using putty with programs that bind keys to CTRL-S may be slighly problematic since putty will send XOFF, which will basically freeze your terminal until you send XON (CTRL-Q).

To disable XOFF, add to your .bashrc file the following lines:

stty ixany
stty ixoff -ixon
stty stop undef
stty start undef

Hit Shift + D, then enter ~s .* to delete all messages in your inbox.

Shell scripts will not run if there is a return carriage at the end of the line, something that’s added from windows machine.

cat filename | tr -d "\r" > filename

After upgrading to Opera 11, by default, the address bar no longer shows the complete URL. To change this behavior, go to:

opera:config#UserPrefs|ShowFullURL

and enable “Show Full URL” by checking the checkbox and then click save below.

This guide will setup Ubuntu 10.10 PXE live cd boot using NFS.

1. Setup your standard PXE server (tftp + dhcp) such that your files are under /tftpboot. Under CentOS, this is accomplished by

yum install tftp tftp-server xinetd syslinux

• tftp/tftp-server is for the tftp server which is required to boot off PXE
• xinetd is the super server which launches the tftp server when requested
• syslinux contains pxelinux.0. This can also be found on some linux distribution images

2. Download the Ubuntu 10.10 iso.
3. Either mount the iso and extract the files to /tftpboot/images/ubuntu1010

 mount -o loop ubuntu-10.10-desktop-i386.iso  /mnt
cp -a /mnt/. /tftpboot/images/ubuntu1010
umount /mnt

or mount the iso directly to /tftpboot/images/ubuntu1010

mount -o loop ubuntu-10.10-desktop-i386.iso  /tftpboot/images/ubuntu1010

4. Add the following entry to your /tftpboot/pxelinux.cfg/default

label 2
        kernel /images/ubuntu1010/casper/vmlinuz
        append root=/dev/nfs boot=casper netboot=nfs nfsroot=10.1.1.6:/tftpboot/images/ubuntu1010 initrd=/images/ubuntu1010/casper/initrd.lz quiet splash --

5. Add the following entry to your /etc/exports

/tftpboot/images/ubuntu1010 10.1.1.0/24(async,no_root_squash,no_subtree_check,ro)

• /tftpboot/images/ubuntu1010 – the location which is to be shared via NFS
• 10.1.1.0/24 – the IPs which are allowed to access this share. Change this to match your network IPs.

6. Start/restart your NFS server
7. Your PXE boot should now work. When greeted with your pxe screen, enter ‘2’ (or whatever was set as your label in the pxe config file), and ubuntu should should begin booting.

After manually compiling apache, there doesn’t seem to be a startup script provided. If that’s the case, use the following for the apache startup script (taken from http://www.faqs.org/docs/securing/chap29sec247.html). Place it in /etc/init.d/ with 755 chmod & root ownership and group.

If you compiled apache to a different location, outside of the usual PATH, you need to specify the full path to httpd in the script below.

#!/bin/sh
#
# Startup script for the Apache Web Server
#
# chkconfig: 345 85 15
# description: Apache is a World Wide Web server. It is used to serve 
# HTML files and CGI.
# processname: httpd

# Source function library.
. /etc/rc.d/init.d/functions

# See how we were called.
case "$1" in
	start)
		echo -n "Starting httpd: "
		daemon /path/to/apache/bin/httpd -DSSL
		echo
		touch /var/lock/subsys/httpd
		;;
	stop)
		echo -n "Shutting down http: "
		killproc httpd
		echo
		rm -f /var/lock/subsys/httpd
		rm -f /var/run/httpd.pid
		;;
	status)
		status httpd
		;;
	restart)
		$0 stop
		$0 start
		;;
	reload)
		echo -n "Reloading httpd: "
		killproc httpd -HUP
		echo
		;;
	*)
		echo "Usage: $0 {start|stop|restart|reload|status}"
		exit 1
		esac

exit 0

To search an replace content in multiple files, use sed.

Example:

sed -i -e 's/search/replace/g' *

That will replace ‘search’ with ‘replace’ on every file in the current directory.

To color your shell script output, you will need to echo out an escape sequence \033[$color1;$color2;$stylem.

You can specify one or more colors or styles, just delimit the colors or styles with a semicolon and end the list with a ‘m’.

Color is given as:

Style is given by:

Examples:
To print something as underlined green:

\033[33;4mYellow Underlined Text\033[0m

Example:
Yellow Underlined Text

To print something underlined, red, with a blue background:

\033[31;44;4mRed Underlined with a Blue Background Text\033[0m

Example:
Red Underlined with a Blue Background Text

To print the above without the underline, just remove the ‘4’

\033[31;44mRed with a Blue Background Text\033[0m

Example:
Red with a Blue Background Text

This is probably not the best solution, but this will save me from thinking in the future:

for i in `ls` ; do mv $i `echo $i | awk '{print tolower($1)}'`; done