Zmodem File Transfer With GNU Screen

I've been using screen as my serial terminal (as opposed to minicom or picocom) for a long time now.  Today I had the need to transfer a file from my PC to the embedded device I was connected to with screen.  Networking was not working, and a co-worker reminded me that zmodem was a way to transfer a file over the serial port.  I googled for instructions on exactly how to use zmodem and I found stack overflow answers and blog entries all mentioning GNU screen for doing so, but none of them really explained it right.  Here's what worked for me today.

To transfer a file from my PC to the embedded device:

  1. in screen hit ctrl-a : zmodem catch
  2. in screen, at the linux command-line on your device type: rz
  3. screen will prompt with an sz command, just append the filename to that command and hit enter

Note that this works best if the file is in the same directory as you ran screen from.

  To send a file from the embedded device to your PC:

  1. in screen hit ctrl-a : zmodem catch
  2. in screen, at the linux command-line on your device type: sz <filename>
  3. screen will prompt with an rz command, just hit enter

You only need to run the zmodem catch command once in your screen session.  In fact, you can just put this at the end of your .screenrc and then you will never have to do step 1 at all:

zmodem catch

Comments

Post a Comment

Popular posts from this blog

SystemVerilog Fork Disable "Gotchas"

This is a long post with a lot of SystemVerilog code. The purpose of this entry is to hopefully save you from beating your head against the wall trying to figure out some of the subtleties of SystemVerilog processes (basically, threads). Subtleties like these are commonly referred to in the industry as "Gotchas" which makes them sound so playful and fun, but they really aren't either. I encourage you to run these examples with your simulator (if you have access to one) so that a) you can see the results first hand and better internalize what's going on, and b) you can tell me in the comments if this code works fine for you and I'll know I should go complain to my simulator vendor. OK, I'll start with a warm-up that everyone who writes any Verilog or SystemVerilog at all should be aware of, tasks are static by default. If you do this: module top; task do_stuff ( int wait_time); #wait_time $display ( "waited %0d, then did stuff" , wa...
Read more

'git revert' Is Not Equivalent To 'svn revert'

I just learned that if you have some changes in your working tree that you want to get rid of, you don't type 'git revert' like you might guess. No, that's what cvs, subversion, mercurial, and bazaar (to name a few) use revert to mean, but not git. With git, revert is used to undo actual commits. Thankfully, you can undo your revert with another 'git revert', I just learned. So let me repeat to be clear, if you have changes to your working files that you want to abandon, DO NOT do this: git revert HEAD That will undo your last commit. Do this instead: git reset --hard HEAD I'm glad I have that straightened out now. I'm wondering if /etc was really a good place for me to start out playing with git. UPDATE: Nearly two years later and I'm still getting comments on this. I'm glad I've been able to help people out this way. The discussion in the comments is good, and one thing I'd like to point out is that I now always use...
Read more

SystemVerilog Streaming Operator: Knowing Right from Left

SystemVerilog has this cool feature that is very handy for converting one type of collection of bits into another type of collection of bits.  It's the streaming operator.  Or the streaming concatenation operator.  Or maybe it's the concatenation of streaming expressions (it's also called pack/unpack parenthetically).  Whatever you want to call it, it's nice.  If you have an array of bytes and you want to turn it into an int, or an array of ints that you want to turn into an array of bytes, or if you have a class instance that you want to turn into a stream of bits, then streaming is amazing.  What used to require a mess of nested for-loops can now be done with a concise single line of code. As nice as it is, getting the hang of the streaming operator is tough.  The SystemVerilog 1800-2012 LRM isn't totally clear (at least to me) on the details of how they work.  The statement from the LRM that really got me was this, "The stream_operator <...
Read more