Notes regarding random thoughts about GitHub releases and the retrieval of them via POSIX script.

release-notes.md

Get the Latest Release Tag (Without the GitHub API)

# Yes, I know that cURL isn't part of POSIX but it's pretty ubiquitous. Maybe see if a Wget fallback would be possible? (note: Apparently Wget is not installed on macOS by default)
# The alternative to use cURL (or possibly Wget) is to use the Git "sparse checkout" technique I'm currently utilizing. Yet again, not POSIX. And probably pre-installed on less UNIX-like operating systems than cURL or Wget.
LATEST_RELEASE=$(basename $(curl --head --location --output /dev/null --silent --write-out %{url_effective} https://github.com/jbenner-radham/node-readme-md-cli/releases/latest))

# After messing around with it for a bit, here's a potential Wget (and grep and sed) based alternative.
# So why is `grep` in there you ask? Well apparently `sed` cannot do multiline regex (at least through pipes). So it's just there to get that "Location" header line for `sed` to extract from.
# Also, `sed` uses "basic regular expressions" (apparently "modern regular expressions" are a non-standard extension) which means that the capturing group has to be escaped (e.g., `\(.*\)`)
# Just found out that macOS implemented `sed -r` for GNU sed compatability. So the `sed` part of the pipe could potentially be: `sed -r 's/^Location: (.*) \[following\]$/\1/'` instead.
LATEST_RELEASE=$(basename $(wget --spider --tries 1 https://github.com/jbenner-radham/node-readme-md-cli/releases/latest 2>&1 | grep 'Location: ' | sed 's/^Location: \(.*\) \[following\]$/\1/'))

# The new versions of Fedora ship with Wget2 instead of Wget. Wget2 is interesting... it doesn't display location headers in addition to other oddities. But, I figured something out.
LATEST_RELEASE=$(basename $(wget2 --method HEAD --output-document /dev/null --stats-site human:- --tries 1 --quiet https://github.com/jbenner-radham/node-readme-md-cli/releases/latest | tail -n 1) | tail -n 1)

# Okay, so HTTPie is **DEFINITELY** not in POSIX... but I was curious so here's what I came up with.
LATEST_RELEASE=$(basename $(http --headers https://github.com/jbenner-radham/node-readme-md-cli/releases/latest | grep 'Location: ' | sed -r 's/^Location: (.+)$/\1/'))

# Yet again, not POSIX (especially since we're adding `jq` to the mix). But I thought this curiosity was worth documenting.
# GitHub supports HTTP content negotiation, so requesting a JSON version of a page will give you a JSON representation.
# I would hope they don't rate limit this like they do with their API, but you never know. So I wouldn't rely on it without testing.
LATEST_RELEASE=$(http --body --follow https://github.com/jbenner-radham/node-readme-md-cli/releases/latest Accept:application/json | jq --raw-output .tag_name)

# Or if needed, without the "v" prefix...
UNPREFIXED_LATEST_RELEASE="${LATEST_RELEASE#v}"

Get the Version From a Release Artifact

cat dist/theme.yml | head -n 1 | sed 's/^# Belmont Theme for Eza v\(.*\)$/\1/'

Extract Major, Minor, and Patch From Version

# Using sed.
MAJOR_MINOR_VERSION=$(echo "0.1.2" | sed 's/^\([0-9]*\)\.\([0-9]*\)\.\([0-9]*\)$/\1\.\2/')
PATCH_VERSION=$(echo "0.1.2" | sed 's/^\([0-9]*\)\.\([0-9]*\)\.\([0-9]*\)$/\3/')

# Using cut (this appears to be POSIX, but double check.) Of note, cut is 1 indexed instead of 0 indexed.
MAJOR_MINOR_VERSION=$(echo "0.10.2" | cut -d . -f 1,2)
PATCH_VERSION=$(echo "0.10.2" | cut -d . -f 3)

Compare Versions

if [ $INSTALLED_MAJOR_MINOR_VERSION -lt $LATEST_MAJOR_MINOR_VERSION ]; then
  # Update...
elif [ $INSTALLED_MAJOR_MINOR_VERSION = $LATEST_MAJOR_MINOR_VERSION ] && [ $INSTALLED_PATCH_VERSION -lt $LATEST_PATCH_VERSION ]; then
  # Update
else
  # Don't Update
fi

Creating a Compressed Release Artifact (Consisting of One File)

# Creating a zip.
# The `zip` command is not listed as being part of POSIX in it's man page. That's probably not a problem for *creating* release artifacts though.
zip theme.zip theme.yaml

# Creating a gzipped tarball.
# Surprisingly `tar` is apparently not currently a part of POSIX. Looks like it was added to the standard in 1996, but then removed from it in 2001. Yet again, that's probably not a problem for *creating* release artifacts though.
# Listing what the flag names mean below. I would use the long flags for clarity (e.g., `--create` over `-c`), but they don't seem to be portable across operating systems in all cases.
# * The `-c` flag stands for "create"
# * The `-z` flag stands for "gzip" (or "gunzip" depending on the context)
# * The `-f` flag stands for "file" and requires a specified filename argument.
tar -czf theme.tar.gz theme.yaml

Extracting a Compressed Release Artifact (Consisting of One File)

# Unzipping a file to the current directory.
# * The `-q` flag stands for "quiet" and just means do not echo out the extracted file names
unzip -q theme.zip

# Alternatively, unzipping to a different directory.
# * The `-d` flag stands for "directory" or more specifically the extraction directory.
unzip -qd "${EZA_CONFIG_DIR}" theme.zip

# Extracting a gzipped tarball to the current directory.
# * The `-x` flag stands for "extract"
# * The `-z` flag stands for "gunzip" (or "gzip" depending on the context)
# * The `-f` flag stands for "file" and requires a specified filename argument.
tar -xzf theme.tar.gz

# Alternatively, gunzipping to a different directory.
# * The `-C` flag stands for "change" (as in "change directory") and it signifies that `tar` should change directories after opening the archive but before extracting.
tar -xzf theme.tar.gz -C "${EZA_CONFIG_DIR}"

File Sizes

Interestingly, at least in the case of a singular YAML file Zip has better compression than GZip (although nothing crazy).

• theme.yaml: 5.9k
• theme.tar.gz: 1.7k
• theme.zip: 1.5k

Potential Release Filenames

• belmont-theme-for-eza-0.1.0.zip
• belmont-theme-for-eza-0.1.0.tar.gz

Maybe offer just a pure YAML download too?

• belmont-theme-for-eza-0.1.0.yaml