Example: Step by step walkthrough with `appimageupdatetool`

Writeup not yet complete!

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This is a step by step walkthrough about the usage of appimageupdatetool. That tool is for the command line only. (It has a sibling tool though which has a graphical user interface, called AppImageUpdate.) Of course it also ships as an AppImage!. However, when I downloaded it, I immediately renamed it from appimageupdatetool-185-1c72f3b-x86_64.AppImage to a shorter name I prefer for typing in the terminal, aiut.

wget  https://github.com/AppImage/AppImageUpdate/releases/download/continuous/appimageupdatetool-185-1c72f3b-x86_64.AppImage -O ~/bin/aiut
chmod +x ~/bin/aiut      # Make it executable !

In my following protocol, I captured as much details as possible -- so be patient...

To not confuse readers too much about my shorthand naming of the tool, I also created a symlink named `appimageupdatetool, which I will use for this walkthrough:

ln -s aiut ~/bin/appimageupdatetool

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If you paid close attention, you'll already start to draw two conclusions:

1. AppImages do not seem to require the use of the .AppImage filename suffix!
2. AppImages seem to work even when called via symbolic links!

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--help

First, get an overview of the tool:

$> appimageupdatetool -h
  /tmp/.mount_aiktbOwQ9Wq/usr/bin/appimageupdatetool {OPTIONS} [path]

    AppImage companion tool taking care of updates for the commandline.

  OPTIONS:

      -h, --help
      -V, --version                     Display version and exit.
      -d, --describe                    Parse and describe AppImage and its
                                        update information and exit.
      -j, --check-for-update            Check for update. Exits with code 1 if
                                        changes are available, 0 if there are
                                        not,other non-zero code in case of
                                        errors.
      -O, --overwrite                   Overwrite existing file. If not
                                        specified, a new file will be created,
                                        and the old one will remain untouched.
      -r, --remove-old                  Remove old AppImage after successful
                                        update
      --self-update
      path                              path to AppImage
      "--" can be used to terminate flag options and force all following
      arguments to be treated as positional options

--describe | -d and --check-for-updates | -j

Looking at the info appimageupdatetool could provide, the -j and -d flags look promising:

 -d, --describe                    Parse and describe AppImage and its
                                   update information and exit.

 -j, --check-for-update            Check for update. Exits with code 1 if
                                   changes are available, 0 if there are
                                   not,other non-zero code in case of
                                   errors.

These help hints suggest (to me at least), that -j is meant for rather silent runs, whereas -d is verbose.

However, both are "verbose". In a way that is a bit inconsistent...

To show how AppImage updates work, I used zsync2-105-7fd1caa-x86_64.AppImage to test (knowing that zsync2-106-817978a-x86_64.AppImage{,.zsync} are already available on their respective GitHub release page and should serve as update seeds). Then I ran these two commands:

$> appimageupdatetool -d zsync2-105-7fd1caa-x86_64.AppImage  1>out_d  2>err_d ; echo $?
  0
$> appimageupdatetool -j zsync2-105-7fd1caa-x86_64.AppImage  1>out_d  2>err_d ; echo $?
  1

Now for the outputs of the two commands. I prepend ERR: and OUT: to each line to show which lines go out which channel.

Param -d:

ERR: Fetching release information for tag "continuous" from GitHub API.
ERR:
OUT: Parsing file: /home/kp/AppImages/zsync2-105-7fd1caa-x86_64.AppImage
OUT: AppImage type: 2
OUT: Raw update information: gh-releases-zsync|TheAssassin|zsync2|continuous|zsync2-*x86_64.AppImage.zsync
OUT: Update information type: ZSync via GitHub Releases
OUT: Assembled ZSync URL: https://github.com/AppImage/zsync2/releases/download/continuous/zsync2-106-817978a-x86_64.AppImage.zsync

Param -j: (out_j is empty)

ERR: Fetching release information for tag "continuous" from GitHub API.

Run first update process

Now run an update process:

$> appimageupdatetool ~/AppImages/zsync2-105-7fd1caa-x86_64.AppImage  ; echo $?

Checking for updates...
Fetching release information for tag "continuous" from GitHub API.
... done!
Starting update...

Fetching release information for tag "continuous" from GitHub API.
0% done
Updating from GitHub Releases via ZSync
0% done
zsync2: /home/kp/AppImages/zsync2-106-817978a-x86_64.AppImage found, using as seed file
zsync2: Target file: /home/kp/AppImages/zsync2-106-817978a-x86_64.AppImage
zsync2: Reading seed file: /home/kp/AppImages/zsync2-105-7fd1caa-x86_64.AppImage
0.59778% done (0.01 of 2.29 MiB)...
zsync2: Reading seed file: /home/kp/AppImages/zsync2-106-817978a-x86_64.AppImage
zsync2: Usable data from seed files: 100.000000%
zsync2: Renaming temp file
zsync2: Fetching remaining blocks
zsync2: Verifying downloaded file
zsync2: checksum matches OK
zsync2: used 2398208 local, fetched 0
100.00% done (2.29 of 2.29 MiB)...
Update successful. New file created: /home/kp/AppImages/zsync2-106-817978a-x86_64.AppImage
0

Yes, I had zsync2-106-817978a-x86_64.AppImage already locally available -- hence the four lines
"zsync2: /home/kp/AppImages/zsync2-106-817978a-x86_64.AppImage found, using as seed file",
"zsync2: Reading seed file: /home/kp/AppImages/zsync2-106-817978a-x86_64.AppImage",
"zsync2: Usable data from seed files: 100.000000%" and
"zsync2: used 2398208 local, fetched 0".

Second round for update process

Last I remove the existing, most up to date zsync2-106-817978a-x86_64.AppImage. We should now see the update process when it really does some heavy lifting:

$> rm -rf zsync2-106-817978a-x86_64.AppImage
$> appimageupdatetool ~/AppImages/zsync2-105-7fd1caa-x86_64.AppImage ; echo $?

Checking for updates...
Fetching release information for tag "continuous" from GitHub API.
... done!
Starting update...

Fetching release information for tag "continuous" from GitHub API.
0% done
Updating from GitHub Releases via ZSync
0% done
zsync2: Target file: /home/kp/AppImages/zsync2-106-817978a-x86_64.AppImage
zsync2: Reading seed file: /home/kp/AppImages/zsync2-105-7fd1caa-x86_64.AppImage
zsync2: Usable data from seed files: 48.761742%
zsync2: Renaming temp file
zsync2: Fetching remaining blocks
48.76% done (1.11 of 2.29 MiB)...
zsync2: Downloading from https://github-production-release-asset-2e65be.s3.amazonaws.com/105511842/13b63fa8-f04c-11e7-9b2d-9124208a76e2?X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Credential=AKIAIWNJYAX4CSVEH53A%2F20180112%2Fus-east-1%2Fs3%2Faws4_request&X-Amz-Date=20180112T024939Z&X-Amz-Expires=300&X-Amz-Signature=c251c07d3fe9e38fbae195c84ea8ad8e176006ebe38d0fe14e2bab1710c72a79&X-Amz-SignedHeaders=host&actor_id=0&response-content-disposition=attachment%3B%20filename%3Dzsync2-106-817978a-x86_64.AppImage&response-content-type=application%2Foctet-stream
99.57% done (2.28 of 2.29 MiB)...
zsync2: Verifying downloaded file
zsync2: checksum matches OK
zsync2: used 1169408 local, fetched 1228208
100.00% done (2.29 of 2.29 MiB)...
Update successful. New file created: /home/kp/AppImages/zsync2-106-817978a-x86_64.AppImage
0