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Archive for the ‘Technical Miscellany’ Category

GNU tar Header Errors?

July 30, 2012 1 comment

Dealing with GNU/tar’s Extended Header Warnings

I tar’d files up on a FreeBSD host and transferred them to a linux host. When extracting the tarball, I was presented with the following warnings:

GNU/tar Header Errors

It seems that FreeBSD‘s tar binary utilizes additional headers that GNU tar does not recognize. There are many blog posts about this. The problem appears to affect tarballs created on various operating systems that employ varying versions of tar and extracting those tarballs with GNU tar.

Generally speaking, these warning can be ignored. On the command line, the files contained within the tarball will still extract (or at least they have every time I’ve encountered this). This does, however, present a problem if one is programmatically encountering this. One can resolve this by addressing the issue within their code or by using the same version of tar on each platform to create and extract the tarballs in question.

Categories: FreeBSD, Technical Miscellany

Using screen to connect to serial ports

June 22, 2012 2 comments

Using screen to connect to serial ports

screen is cool. screen is an indespencable tool to any unix administrator. My challenge was to find a solution to connect to the serial port on a server chassis. The solution I found was to utilize a USB-Serial adapter (and associated Mac OS X Lion Driver), null modem cable, and rj45-db9 adapter in conjunction with screen.

screen, being a key tool in an administrator’s tool box, was found to have the capability of connecting to serial ports!

To connect to the serial port:

screen /dev/tty.PL2303-000013FD

Specifying baud rate:

screen /dev/tty.PL2303-000013FD 9600

Enabling CTS/RTS:

screen /dev/tty.PL2303-000013FD 9600,ctsrts

Terminate the session using screen command ^a,k

Notes

  • Your tty will likely differ. I was using a PL2303 based USB-Serial adapter within Mac OS X 10.7 (aka Lion)
  • A driver for this USB-Serial adapter were difficult to find, so I will link to it here
  • I downloaded the driver from here
Categories: Technical Miscellany