Converting RAR to ZIP in Linux

As ever, mostly notes to myself.

RAR is a silly and proprietary format. I prefer free software and I find that ZIP files are smaller and decompress faster. Not everyone agrees, and that's fine. Assuming you've downloaded a RAR file and want to convert it to ZIP, what's the easiest way?

Install P7Zip

sudo apt-get install p7zip-full p7zip-rar

Script

This basic bash script will

1. Extract a RAR example.rar file to a temporary directory on a RAM disk.
2. Recompress to example.zip.
3. Delete the temporary directory.

Easy!

It is based on this conversion from CBR to CBZ.

 BASH#!/bin/bash

echo "Converting RARs to ZIPs"



# Separate files using ␜ http://graphemica.com/%E2%90%9C.

IFS="␜"



# Use RAM disk for temporary files.

WORKDIR="/dev/shm/"



# Set name for the temp dir. This directory will be created under WORKDIR

TEMPDIR="rar2zip"



# Run using "./rar2zip.sh /full/path/to/files/"

# If no directory is specified, then use the current working directory (".").



if test -z $1; then

   SOURCEDIR=`pwd`

else

   SOURCEDIR="$1"

fi



echo "Using $SOURCEDIR"



# Create an temporary directory to work in.

cd $WORKDIR

mkdir $TEMPDIR

cd $TEMPDIR



# Find all the .rar files in the specified directory.

# Using -iname means it will find .rar .RAR .RaR etc.

# "-printf "%p␜" will cause the file names to be separated by the ␜ symbol,

# rather than the default newline.



for OLDFILE in `find $SOURCEDIR -iname "*.rar" -printf "%p␜"`; do



   # Get the file name without the extension

   BASENAME=`basename "${OLDFILE%.*}"`



   # Path for the file. The ".zip" file will be moved there.

   DIRNAME=`dirname $OLDFILE`



   # Name of the .zip file

   NEWNAME="$BASENAME.zip"



   # Create a temporary folder for unRARed files

   echo "Extracting $OLDFILE"

   mkdir "$BASENAME"

   7z x "$OLDFILE" -O"$BASENAME"

   cd "$BASENAME"



   # Zip the files with maximum compression

   7z a -tzip -mx=9 "$NEWNAME" *

   # Alternative. MUCH SLOWER, but better compression

   # 7z a -mm=Deflate -mfb=258 -mpass=15 -r "$NEWNAME" *



   # Move the new .zip to the directory containing the original ".rar" file

   mv "$NEWNAME" $DIRNAME/"$NEWNAME"



   # Delete the temporary directory

   cd $WORKDIR

   rm -r "$BASENAME"



   # OPTIONAL. Delete the RAR file

   # cd $DIRNAME

   # rm "$OLDFILE"



done



# Delete the temporary directory

cd $WORKDIR

rm -r $TEMPDIR



echo "Conversion Done"

That's it! I suppose it might be nice if there were a simpler way to do it - but this is fairly quick and error-proof.