TOPIC: BASH
Automating Positron and RStudio updates on Linux Mint 22
6th November 2025Elsewhere, I have written about avoiding manual updates with VSCode and VSCodium. Here, I come to IDE's produced by Posit, formerly RStudio, for data science and analytics uses. The first is a more recent innovation that works with both R and Python code natively, while the second has been around for much longer and focusses on native R code alone, though there are R packages allowing an interface of sorts with Python. Neither are released via a PPA, necessitating either manual downloading or the scripted approach taken here for a Linux system. Each software tool will be discussed in turn.
Positron
Now, we work through a script that automates the upgrade process for Positron. This starts with a shebang line calling the bash executable before moving to a line that adds safety to how the script works using a set statement. Here, the -e switch triggers exiting whenever there is an error, halting the script before it carries on to perform any undesirable actions. That is followed by the -u switch that causes errors when unset variables are called; normally these would be assigned a missing value, which is not desirable in all cases. Lastly, the -o pipefail switch causes a pipeline (cmd1 | cmd2 | cm3) to fail if any command in the pipeline produces an error, which can help debugging because the error is associated with the command that fails to complete.
#!/bin/bash
set -euo pipefailThe next step then is to determine the architecture of the system on which the script is running so that the correct download is selected.
ARCH=$(uname -m)
case "$ARCH" in
x86_64) POSIT_ARCH="x64" ;;
aarch64|arm64) POSIT_ARCH="arm64" ;;
*) echo "Unsupported arch: $ARCH"; exit 1 ;;
esacOnce that completes, we define the address of the web page to be interrogated and the path to the temporary file that is to be downloaded.
RELEASES_URL="https://github.com/posit-dev/positron/releases"
TMPFILE="/tmp/positron-latest.deb"Now, we scrape the page to find the address of the latest DEB file that has been released.
echo "Finding latest Positron .deb for $POSIT_ARCH..."
DEB_URL=$(curl -fsSL "$RELEASES_URL" \
| grep -Eo "https://cdn\.posit\.co/[A-Za-z0-9/_\.-]+Positron-[0-9\.~-]+-${POSIT_ARCH}\.deb" \
| head -n 1)If that were to fail, we get an error message produced before the script is aborted.
if [ -z "${DEB_URL:-}" ]; then
echo "Could not find a .deb link for ${POSIT_ARCH} on the releases page"
exit 1
fiShould all go well thus far, we download the latest DEB file using curl.
echo "Downloading: $DEB_URL"
curl -fL "$DEB_URL" -o "$TMPFILE"When the download completes, we try installing the package using apt, much like we do with a repo, apart from specifying an actual file path on our system.
echo "Installing Positron..."
sudo apt install -y "$TMPFILE"Following that, we delete the installation file and issue a message informing the user of the task's successful completion.
echo "Cleaning up..."
rm -f "$TMPFILE"
echo "Done."When I do this, I tend to find that the Python REPL console does not open straight away, causing me to shut down Positron and leaving things for a while before starting it again. There may be temporary files that need to be expunged and that needs its own time. Someone else might have a better explanation that I am happy to use if that makes more sense than what I am suggesting. Otherwise, all works well.
RStudio
A lot of the same processing happens during the script updating RStudio, so we will just cover the differences. The set -x statement ensures that every command is printed to the console for the debugging that was needed while this was being developed. Otherwise, much code, including architecture detection, is shared between the two apps.
#!/bin/bash
set -euo pipefail
set -x
# --- Detect architecture ---
ARCH=$(uname -m)
case "$ARCH" in
x86_64) RSTUDIO_ARCH="amd64" ;;
aarch64|arm64) RSTUDIO_ARCH="arm64" ;;
*) echo "Unsupported architecture: $ARCH"; exit 1 ;;
esacFiguring out the distro version and the web page to scrape was where additional effort was needed, and that is reflected in some of the code that follows. Otherwise, many of the ideas applied with Positron also have a place here.
# --- Detect Ubuntu base ---
DISTRO=$(grep -oP '(?<=UBUNTU_CODENAME=).*' /etc/os-release || true)
[ -z "$DISTRO" ] && DISTRO="noble"# --- Define paths ---
TMPFILE="/tmp/rstudio-latest.deb"
LOGFILE="/var/log/rstudio_update.log"
echo "Detected Ubuntu base: ${DISTRO}"
echo "Fetching latest version number from Posit..."
# --- Get version from Posit's official RStudio Desktop page ---
VERSION=$(curl -s https://posit.co/download/rstudio-desktop/ \
| grep -Eo 'rstudio-[0-9]+\.[0-9]+\.[0-9]+-[0-9]+' \
| head -n 1 \
| sed -E 's/rstudio-([0-9]+\.[0-9]+\.[0-9]+-[0-9]+)/\1/')
if [ -z "$VERSION" ]; then
echo "Error: Could not extract the latest RStudio version number from Posit's site."
exit 1
fi
echo "Latest RStudio version detected: ${VERSION}"
# --- Construct download URL (Jammy build for Noble until Noble builds exist) ---
BASE_DISTRO="jammy"
BASE_URL="https://download1.rstudio.org/electron/${BASE_DISTRO}/${RSTUDIO_ARCH}"
FULL_URL="${BASE_URL}/rstudio-${VERSION}-${RSTUDIO_ARCH}.deb"
echo "Downloading from:"
echo " ${FULL_URL}"
# --- Validate URL before downloading ---
if ! curl --head --silent --fail "$FULL_URL" >/dev/null; then
echo "Error: The expected RStudio package was not found at ${FULL_URL}"
exit 1
fi
# --- Download and install ---
curl -L "$FULL_URL" -o "$TMPFILE"
echo "Installing RStudio..."
sudo apt install -y "$TMPFILE" | tee -a "$LOGFILE"
# --- Clean up ---
rm -f "$TMPFILE"
echo "RStudio update to version ${VERSION} completed successfully." | tee -a "$LOGFILE"When all ended, RStudio worked without a hitch, leaving me to move on to other things. The next time that I am prompted to upgrade the environment, this is the way I likely will go.
Incorporating tmux in a terminal workflow
11th March 2025As part of a recent workstation upgrade and subsequent AI explorations to see what runs on a GPU, I got to use tmux to display two panes within a terminal session on Linux Mint, each with output from a different system monitoring command; one of these was top for monitoring system processes in a more in-depth way. Some of that need has passed, yet I retain tmux and even set to open in a new terminal session by adding the following code to my .bashrc file:
if command -v tmux &> /dev/null && [ -z "$TMUX" ]; then
tmux new
fiThis tests if tmux is installed and that this is not running in an existing tmux session before opening a new tmux session. You can also attach to an existing session or use a new default session if you like. That changes the second line of the above code to this:
tmux attach -t default || tmux new -s default
Wanting to have everything fresh in a new session, I decided against that. While I have gone away from using tmux panes for the moment, there is a cheat sheet that could have uses if I do, and another post elsewhere describes resizing the panes too, which came in very useful for that early dalliance while system monitoring.
Unzipping more than one file at a time in Linux and macOS
10th September 2024To me, it sounded like a task for shell scripting, but I wanted to extract three zip archives in one go. They had come from Google Drive and contained different splits of the files that I needed, raw images from a camera. However, I found a more succinct method than the line of code that you see below (it is intended for the BASH shell):
for z in *.zip; do; unzip "$z"; done
That loops through each file that matches a glob string. All I needed was something like this:
unzip '*.zip'
Without embarking on a search, I got close but have not quoted the search string. Without the quoting, it was not working for me. To be sure that I was extracting more than I needed, I made the wildcard string more specific for my case.
Once the extraction was complete, I moved the files into a Lightroom Classic repository for working on them later. All this happened on an iMac, but the extraction itself should work on any UNIX-based operating system, so long as the shell supports it.
Using associative arrays in scripting for BASH version 4 and above
29th April 2023Associated arrays get called different names in different computing languages: dictionaries, hash tables and so on. What is held in common is that they essentially are lists of key value pairs. In the case of BASH, you need at least version 4 to make use of this facility. In Linux Mint, I get 5.1.16, but macOS users apparently are still on BASH 3, so this post may not help them.
To declare an associative array in a later version of BASH, the following command gets issued:
declare -A hashtable
The code to add a key value pair then takes the following form:
hashtable[key1]=value1
Several values can be added to an empty array like this:
hashtable=( ["key1"]="value1" ["key2"]="value2" )
Declaration and instantiation of an associative can be done in the same line as follows:
declare -A hashtable=( ["key1"]="value1 ["key2"]="value2")
Handily, it is possible to loop through the entries in an associative array. It is possible to do this for keys and for values, once you expand out the appropriate list. The following expands a list of values:
"${hashtable[@]}"
Expanding a list of values needs something like this:
"${!hashtable[@]}"
Looping through a list of values needs something like the following:
for val in "${hashtable[@]}"; do echo "$val"; done;
The above has been placed on a single line with semicolon delimiters for brevity, but this can be put on several lines with no semicolons for added clarity as long as correct indentation is followed. It is also possible to similarly loop through a list of keys:
for key in "${!hashtable[@]}"; do echo "key: $key, value ${hashtable[$key]}"; done;
For the example associative array declared earlier, the last line produces this output, resolving the value using the supplied key:
key: key2, value value2
key: key1, value value1
All of this found a use in a script that I created for adding new Markdown files to a Hugo instance because there was more than one shortcode that I wished to apply due to my having more than one content directory in use.
String replacement in BASH scripting
28th April 2023During creation of new posts for a Hugo deployed website, I found myself using the same directories again and again. Since I invariably ended up making typing mistakes when I did so, I fancied the idea of using shortcodes instead.
Because I wanted to turn the shortcode into the actual directory name, I chose the use of text replacement in BASH scripting. Thankfully, this is simple and avoids the use of regular expressions, which can bring their own problems. The essential syntax is as follows:
variable="${variable/search text/replacement}"
For the variable, the search text is substituted with the replacement straightforwardly. It is even possible to include the search and replacement text in variables. In the example below, this is achieved using variables called original and replacement.
variable="${variable/$original/$replacement}"
Doing this got me my translatable shortcodes and converted them into actual directory names for the hugo command to process. There may be other uses yet.
Resolving a clash between Homebrew and Python
22nd November 2022For reasons that I cannot recall now, I installed the Hugo static website generator on my Linux system and web servers using Homebrew. The only reason that I suggest is that it might have been a way to get the latest version at the time because Linux Mint only does major changes like that every two years, keeping it in line with long-term support editions of Ubuntu.
When Homebrew was installed, it changed the lookup path for command line executables by adding the following line to my .bashrc file:
eval "$(/home/linuxbrew/.linuxbrew/bin/brew shellenv)"
This executed the following lines:
export HOMEBREW_PREFIX="/home/linuxbrew/.linuxbrew";
export HOMEBREW_CELLAR="/home/linuxbrew/.linuxbrew/Cellar";
export HOMEBREW_REPOSITORY="/home/linuxbrew/.linuxbrew/Homebrew";
export PATH="/home/linuxbrew/.linuxbrew/bin:/home/linuxbrew/.linuxbrew/sbin${PATH+:$PATH}";
export MANPATH="/home/linuxbrew/.linuxbrew/share/man${MANPATH+:$MANPATH}:";
export INFOPATH="/home/linuxbrew/.linuxbrew/share/info:${INFOPATH:-}";
While the result suits Homebrew, it changed the setup of Python and its packages on my system. Eventually, this had undesirable consequences, like messing up how Spyder started, so I wanted to change this. There are other things that I have automated using Python and these were not working either.
One way that I have seen suggested is to execute the following command, but I cannot vouch for this:
brew unlink python
What I did was to comment out the offending line in .bashrc and replace it with the following:
export PATH="$PATH:/home/linuxbrew/.linuxbrew/bin:/home/linuxbrew/.linuxbrew/sbin"
export HOMEBREW_PREFIX="/home/linuxbrew/.linuxbrew";
export HOMEBREW_CELLAR="/home/linuxbrew/.linuxbrew/Cellar";
export HOMEBREW_REPOSITORY="/home/linuxbrew/.linuxbrew/Homebrew";
export MANPATH="/home/linuxbrew/.linuxbrew/share/man${MANPATH+:$MANPATH}:";
export INFOPATH="${INFOPATH:-}/home/linuxbrew/.linuxbrew/share/info";
The first command adds Homebrew paths to the end of the PATH variable rather than the beginning, which was the previous arrangement. This ensures system folders are searched for executable files before Homebrew folders. It also means Python packages load from my user area instead of the Homebrew location, which happened under Homebrew's default configuration. When working with Python packages, remember not to install one version at the system level and another in your user area, as this creates conflicts.
So far, the result of the Homebrew changes is not unsatisfactory, and I will watch for any rough edges that need addressing. If something comes up, then I will set things up in another way.
Accessing Julia REPL command history
4th October 2022In the BASH shell used on Linux and UNIX, the history command calls up a list of recent commands used and has many uses. There is a .bash_history file in the root of the user folder that logs and provides all this information, so there are times when you need to exclude some commands from there, but that is another story.
The Julia REPL environment works similarly to many operating system command line interfaces, so I wondered if there was a way to recall or refer to the history of commands issued. So far, I have not come across an equivalent to the BASH history command for the REPL itself, but there the command history is retained in a file like .bash_history. The location varies on different operating systems, though. On Linux, it is ~/.julia/logs/repl_history.jl while it is %USERPROFILE%\.julia\logs\repl_history.jl on Windows. While I tend to use scripts that I have written in VSCode rather than entering pieces of code in the REPL, the history retains its uses. Thus, I am sharing it here for others. In the past, the location changed, but these are the ones with Julia 1.8.2, the version that I have at the time of writing.
Reloading .bashrc within a BASH terminal session
3rd July 2016BASH is a command-line interpreter that is commonly used by Linux and UNIX operating systems. Chances are that you will find yourself in a BASH session if you start up a terminal emulator in many of these, though there are others like KSH and SSH too.
BASH comes with its own configuration files and one of these is located in your own home directory, .bashrc. Among other things, it can become a place to store command shortcuts or aliases. Here is an example:
alias us='sudo apt-get update && sudo apt-get upgrade'
Such a definition needs there to be no spaces around the equals sign, and the actual command to be declared in single quotes. Doing anything other than this will not work, as I have found. Also, there are times when you want to update or add one of these and use it without shutting down a terminal emulator and restarting it.
To reload the .bashrc file to use the updates contained in there, one of the following commands can be issued:
source ~/.bashrc
. ~/.bashrc
Both will read the file and execute its contents so you get those updates made available so you can continue what you are doing. There appears to be a tendency for this kind of thing in the world of Linux and UNIX because it also applies to remounting drives after a change to /etc/fstab and restarting system services like Apache, MySQL or Nginx. The command for the former is below:
sudo mount -a
Often, the means for applying the sorts of in-situ changes that you make are simple ones too, and anything that avoids system reboots has to be good since you have less work interruptions.
Turning on autocompletion for the bash shell in terminal sessions
26th June 2013At some point, I managed to lose the ability to have tab-key-based autocompletion on terminal sessions on my Ubuntu GNOME machine. Wanting it caused had me to turn to the web for an answer, and I found it on a Linux Mint forum; the bash shell is so pervasive in the UNIX and Linux worlds that you can look anywhere for a fix like this.
The problem centred around the .bashrc file in my home area. It does have quite a few handy custom aliases, and I must have done a foolish spring-clean on the file sometime. That is the only way that I can explain how the following lines got removed:
if [ -f /etc/bash_completion ]; then
. /etc/bash_completion
fiWhat they do is look to see if /etc/bash_completion can be found on your system and to use it for tab-based autocompletion. With the lines not in .bashrc, it couldn't happen. Others may replace bash_completion with bash.bashrc to get a fuller complement of features, but I'll stick with what I have for now.
Using Korn shell commands in scripts running under the bash shell
19th May 2007This is actually a fairly simple one: just prefix the relevant command with ksh like below (in the example below, bash won't know what to do with the print command otherwise):
ksh print "Hello, world!"
It's also useful for running Korn shell scripts under the bash shell as well.