Extracting zip file and then cd into it with different filename - linux

Question

I am creating a bash script to extract a tar file and cd'ing into it and then it runs another script. So far this has been working pretty well with my code below, however, i ran into a case where if the extracted folder is different than the .tar file name then it would cause an issue. So my question is, how should I handle unique cases where the file name is different than then .tar filename.
e.g,) my_file.tar ---> after extraction ----> my_different_file_name
#!/bin/bash
fname=$1
echo the file you are about to extract is $fname
if [ -f $fname ]; then #if the file exists
tar -xvzf $fname #tar it
cd ${fname%.*} #the `%.*` will extract filename from filename.tgz and cd into it
echo ${fname%.*}
echo $PWD
loadIt #another script to load
fi

Answer 1

You could do a:
topDir=$(tar -xvzf $fname | sed "s|/.*$||" | uniq)
[ $(wc -w <<< $topDir) == 1 ] || exit 1
echo topDir=$topDir
Explanation: the first command untars vebosely (outputs all files it's untarring), and then gets all the leading directory names, and pipes them into uniq. (so basically it returns a list of all the top level directories in the tar file). The next line checks that there's exactly one entry in topDir, otherwise it exits.
At this point $topdir will be the directory you want to cd into.

Answer 2

Maybe you could do something like that:
cd $(tar -tf $fname | head -1)

Answer 3

If you don't mind moving the directory around after you extract it you can do something like this
# Create a temporary directory
$ tmpd=$(mktemp -d)
# Change to the temporary directory
$ pushd "$tmpd"
# Extract the tarball
$ tar -xf "$fname"
# Glob the directory name
$ d=(*)
# Error if we have more (or less) than one directory
$ [ "${#d}" = 0 ] || exit 1
# Explicitly use just the first directory (optional since `$d` does the same thing)
$ d=${d[0]}
# Move the extracted directory to the previous directory
$ mv "$d" "$OLDPWD"
# Change back to the starting directory
$ popd
# Remove the (now empty) temporary directory
$ rmdir "$tmpd"
# Change into the extracted directory
$ cd "$d"
# Run 'loadIt'
$ loadIt