IT Systems, Networks, Security and Education
Bash is so powerful it scares me. It’s like Fred Flintstone riding a dinosaur to work: one false move and it’s gonna be mad destruction. So I love me some man pages. I also dig through the better online references. If you want man pages for a specific version of Ubuntu, nothing beats manpages.ubuntu.com. Check …
Virtual machines are great. They’re cool for testing operating systems, and let you deploy machines and add and remove applications and services. But they’re big and resource-intensive. Containers are the new kids. Think in terms of deploying a virtualized application, rather than a whole OS. The big names here are Docker and Kubernetes, with the …
Continue reading “Virtualization 2.0: Containers vs. Virtual Machines”
I recently worked on a migration from OpenVMS to Red Hat Linux, and spent some serious effort porting VMS DCL (Direct Command Line) scripts to Python and Bash. The long-time VMS people were completely unfamiliar with the Linux command line, so we went looking for some good online resources that mapped DCL to Bash. (See …
Continue reading “OpenVMS Commands Mapped to Unix/Linux Equivalents”
This is post 30 of 30 in the series “Introduction to Python” This script is specific to operations moving from VMS to Linux, which requires migrating DCL scripts to Python scripts. #!/bin/bash # processDCL.sh # Glenn Norman 2018 # Uncomment these two lines to prompt for a script name. # This script assumes the …
This is post 29 of 30 in the series “Introduction to Python” Here’s a sample Python/Pexpect script, which is called by the bash script in the previous page. Note how the spawn function runs the command you supply as the argument, in this case “ftp ftp.ubuntu.com”. #!/usr/bin/python # Connects to a public ftp server, downloads …
This is post 28 of 30 in the series “Introduction to Python” Some operations are easily handled in bash, like cleanup functions. And bash can call a main Python routine. #!/bin/bash # Author: Armando S. Romero III # Runs ftpTest.py to do pexpect session, # checks if the file downloaded successfully, # cleans up when …
Continue reading “Python : Using Pexpect : ftpTestOffload.sh”
This is post 27 of 30 in the series “Introduction to Python” Using Pexpect “Pexpect is a pure Python module for spawning child applications; controlling them; and responding to expected patterns in their output. Pexpect works like Don Libes’ Expect. Pexpect allows your script to spawn a child application and control it as if a …
This is post 26 of 30 in the series “Introduction to Python” Go to Chapter 62 of A Smarter Way. In Python, you don’t handle files directly. Instead you create a file handle, which opens the file either read-only or read-write. It is important to close the file when you are done! The with syntax …
This is post 25 of 30 in the series “Introduction to Python” Go to Chapter 51 of A Smarter Way. Recall for loops: http://gnorman.org/2018/10/02/python-for-loops/ for friend in friends: print(“Hello, ” + friend.title() + “!”) For loops are good for meeting a single condition, once. But sometimes you need to keep performing the matching operation. This …
This is post 24 of 30 in the series “Introduction to Python” Go to Chapter 41 in A Smarter Way. A function in Python is like a function in math: you put something in, it gets transformed, and you get something out. There are two stages to using a function, defining it and calling it. …