Linux, supercomputing, and technology.
Very easy and usually accomplished with a loop: $ array=(red green blue) $ for I in ${array[@]}; do echo $I; done red green blue But we can do better!: $ printf '%s\n' "${array[@]}" or: $ ( IFS=$'\n'; echo "${array[*]}" ) Note the switch to "${array[*]}" from "${array[@]}" (the "quoting" is important!…
Out of the box git commit logs are a bit drab. commit f93f639563850136a11c4cbc39a119c6905feaf2 Author: John Westlund <email@addr> Date: Mon Dec 12 15:49:17 2016 -0800 broke some stuff commit 7dc383f214dd9155d78e4542a993607ec07eaa84 Author: Other Dev <email2@addr> Date: Mon Dec 12 15:26:16 2016 -0800…
Go to the project in question an open the " Settings" page. Change the Repository name and click on the Rename button. Github will present you with a warning dialog. If you're renaming a repository that multiple people use you'll want to make sure you've given them a heads up. Next…
There are a few possible solutions that range from pretty straight forward to a little tricky. Process Substitution If you know you'll always be running under a shell that supports process substitution(bash, zsh, ksh93) multiplexing a command's output is pretty easy using tee. tee supports outputting to multiple "files"…
Full credit goes to avbrand.com this technique. I've made some minor tweaks so it will work if you system is configured with a proxy. Remember you're using a web service (https://tohtml.com) to perform the highlighting -- so if the code is really sensitive this may not be…
It can be hard to tell if everything went okay inside a chain of pipes since $? will only report the return code from the final command in the chain. Using a different variable ($PIPESTATUS) the return codes of all the commands chained together can be found. #!/bin/bash # as long…
Using the trap built-in signals received by a scripts (e.g. SIGINT). Using this functionality a script can also take actions based on errors. This can allow some more nuanced handling as opposed to set -e. #!/bin/bash ErrorThreshold=5 Cumulative_RC=0 ErrorCount=0 TrackErrorTrap() { ((Cumulative_RC += $?)) ((ErrorCount++)) if…
There are a lot of overly complicated ways to insert a line after every nth line, but the simplest way I find is the following: sed '0~3 s/$/\nMy Text/g' < input.file In a file with six lines you get something like the following: Line 1 Line…
This is the first of a few articles detailing how to host multiple Node.js or PHP websites on a single EC2 instance. Log in to AWS, and click on EC2 Click on Launch Instance under Create Instance Select the underlying OS you'd like to use. I've chosen Amazon Linux…
Borrowed this from a site I had to pull up via Google's cache with some additions. I recently needed to convert an AWS instance-store AMI to an EBS backed AMI. Here’s the steps I took in order to fix that. It’s a ext3 file system in this example,…