Adding status check (file integrity) to cbr cbz bash script conversion

Question

First post, so hello! Let me start with what I'm talking about programming. I understand very simple stuff, but when it comes to checking exit codes or what is a suitable term, I'm at a loss. Apparently, my search engine is really weak in this area, I think this is a matter of terminology.

Thank you in advance for reading this / answering my question!

Description : I found a script that converts / repackages .cbr files to .cbz. These files are basically your average rar and zip files, however renamed to another extension, as they are used for (comic) book applications like comicrack , qcomicbook , and what not. Surprisingly, there are no cbr → cbz converters. The benefits of .cbz also avoid the proprietary rar file format that you can store metadata from Comic Vine with e. g comictagger .

Problem . Sometimes repackaging files does not end well and, hopefully, will be mitigated by integrity checking and another. I changed the script a bit to use p7zip , since it can like pack / unpack 7z , zip files and some others , i.e. e great for options. p7zip can test the archive:

7z t comicfile.cbz tmpworkingdir 

I assume it is a matter of using if and else here (?) To check the integrity, and then give it one more step if there are any errors.

Question / tl; dr: What would be the “best” / adequate approach for adding file integrity checking to the script below?

 #!/bin/bash #Source: http://comicrack.cyolito.com/forum/13-scripts/30013-cbr3cbz-rar-to-zip-conversion-for-linux echo "Converting CBRs to CBZs" # Set the "field separator" to something other than spaces/newlines" so that spaces # in the file names don't mess things up. I'm using the pipe symbol ("|") as it is very # unlikely to appear in a file name. IFS="|" # Set working directory where to create the temp dir. The user you are using must have permission # to write into this directory. # For performance reasons I'm using ram disk (/dev/shm/) in Ubuntu server. WORKDIR="/dev/shm/" # Set name for the temp dir. This directory will be created under WORDDIR TEMPDIR="cbr2cbz" # The script should be invoked as "cbr2cbz {directory}", where "{directory}" is the # top-level directory to be searched. Just to be paranoid, if no directory is specified, # then default to the current working directory ("."). Let put the name of the # directory into a shell variable called SOURCEDIR. # Note: "$1" = "The first command line argument" if test -z "$1"; then SOURCEDIR=`pwd` else SOURCEDIR="$1" fi echo "Working from directory $SOURCEDIR" # We need an empty directory to work in, so we'll create a temp directory here cd "$WORKDIR" mkdir "$TEMPDIR" # and step into it cd "$TEMPDIR" # Now, execute a loop, based on a "find" command in the specified directory. The # "-printf "$p|" will cause the file names to be separated by the pipe symbol, rather than # the default newline. Note the backtics ("`") (the key above the tab key on US # keyboards). for CBRFILE in `find "$SOURCEDIR" -name "*.cbr" -printf "%p|while read line; do # Now for the actual work. First, extract the base file name (without the extension) # using the "basename" command. Warning: more backtics. BASENAME=`basename $CBRFILE ".cbr"` # And the directory path for that file, so we know where to put the finished ".cbz" # file. DIRNAME=`dirname $CBRFILE` # Now, build the "new" file name, NEWNAME="$BASENAME.cbz" # We use RAR file name to create folder for unpacked files echo "Processing $CBRFILE" mkdir "$BASENAME" # and unpack the rar file into it 7z x "$CBRFILE" -O"$BASENAME" cd "$BASENAME" # Lets ensure the permissions allow us to pack everything sudo chmod 777 -R ./* # Put all the extracted files into new ".cbz" file 7z a -tzip -mx=9 "$NEWNAME" * # And move it to the directory where we found the original ".cbr" file mv "$NEWNAME" $DIRNAME/"$NEWNAME" # Finally, "cd" back to the original working directory, and delete the temp directory # created earlier. cd .. rm -r "$BASENAME" # Delete the RAR file also rm "$CBRFILE" done # At the end we cleanup by removing the temp folder from ram disk cd .. echo "Conversion Done" rm -r "$TEMPDIR" 

Oh mankind, without publishing more than two links up to 10 reputation, and I linked the shit from OP .. [edit] ah .. mh-mmm .. there we go ..

[edit 2] I removed unrar as a dependency and used p7zip instead, since it can extract rar files.

Answer 1

You will need two checks:

• 7z t will check archive integrity

• You should also check the integrity of all image files in the archive. You can use tools like ImageMagick to do this .

  A simple test would be an identify file, but it can only read the header. I would use the convert file -resize 5x5 png:- > /dev/null

  This scales the image to 5x5 pixels, converts it to PNG, and then transfers the result to /dev/null (discarding it). To scale, you need to read the entire image. If this command fails, something is wrong with the image file.