Open Source Operations

# less the youngest file in the dir that is not a dot file.
function lless () {
less `ls -Art1|tail -1`
}



written by admin

I setup dhcpd and tfpt just infrequently enough to forget the details. I’m putting my gottchas here so I don’t forget them.

syslinux package ‘pxelinux’:
pxelinux loads and gets the right IP, then it fails trying to
getting the error “tftp server does not support tsize option”

Fix:

in file /etc/dhcpd.conf:

# absolutly critical to have the next-server line for tftp booting
# when you get "tftp server does not support tsize option" error,
#it's because your missing the config line, Double check with:
#          grep next-server     /etc/dhcpd.conf
#    - Tony 10/17/08
next-server 192.168.0.50;

Troubleshooting:

1] for setting up tftpd you have to make sure there are not entries like
this in /etc/hosts file

127.0.1.1      joust.famemobile.com joust

if so you have to change them to this.

192.168.1.155   joust.famemobile.com joust

2] Using tcpdump for tftp trouble shooting

The fact that loading pxelinux.0 succeeds made me think everything else should work.

The pxelinux.0 loads fine, but the config file ‘pxelinux.cfg/01-00-0c-29-c4-b0-5a’ does not.

05:27:20.882329 IP (tos 0×0, ttl 20, id 2, offset 0, flags [none], proto: UDP (17), length: 55) 192.168.0.51.ah-esp-encap > 192.168.0.50.tftp: [udp sum ok] 27 RRQ “pxelinux.0″ octet tsize 0
05:27:20.893400 IP (tos 0×0, ttl 20, id 4, offset 0, flags [none], proto: UDP (17), length: 60) 192.168.0.51.acp-port > 192.168.0.50.tftp: [udp sum ok] 32 RRQ “pxelinux.0″ octet blksize 1456
05:27:20.953322 IP (tos 0×0, ttl 20, id 29, offset 0, flags [none], proto: UDP (17), length: 91) 192.168.0.51.57089 > 0.0.0.0.tftp: 63 RRQ “pxelinux.cfg/01-00-0c-29-c4-b0-5a” octet tsize 0 blks
… stuff cut out…
05:27:20.972168 IP (tos 0×0, ttl 18, id 44911, offset 0, flags [none], proto: UDP (17), length: 54) 0.0.0.0.tftp > 192.168.0.51.57089: [udp sum ok] 26 ERROR tftp-err-#8 ” tsize option required”

The “0.0.0.0.tftp” is the indicator there is something wrong.

written by admin \\ tags: Add new tag

I always seem to need a tmp file, I used to do ‘vi /tmp/foo’ but it usually had something in it from last time.  This function opens a new file and stores the file name in $f.

I use it like:

vt
<paste some stuff, clean it up>
perl -pe ’s/foo/bar/’ $f

####
function vt () {
    for i in `seq 0 255`;
    do
        FILE=/tmp/$USER-foo-$i;
        if [ -f "$FILE" ]; then
            echo -n '.';
        else
            f=$FILE;
            vi $FILE;
            echo $FILE;
            return;
        fi;
    done
}

###### Cleanup
function cleanvt () {
for i in `seq 0 255`
do
    FILE=/tmp/$USER-foo-$i

    if [ -f "$FILE" ]
    then
    echo -n '.'
    rm $FILE
    else
        echo
        return
fi
done
echo
}

written by admin

No matter how good an admin you are, you’ll eventually delete something by accident.  I don’t like ‘rm -i’,  it’s too much.  I use the trick of typing ‘#’ before the rm command. Tab competion still works but if I mess up and hit tab-enter (like I do a lot) the ‘#’ saves me. When I’ve got the line looking like I want I ‘ctrl-a’ to beginning and delete the ‘#’ and execute the line.

written by admin