Notes

Shell commands

tar

# Say you want to tar blah/user/app,
# To make an archive *with* the outermost folder inside
tar czf achive.tar.gz -C blah/user app
# To make an archive *without* the othermost folder inside
tar czf archive.tar.gz -C blah/user/app .

# To untar
tar xf archive.tar.gz
# To untar to foo/bar
mkdir -p foo/bar # tar will not make the path
tar xf archive -C foo/bar

tar is an odd command, where you invoke it from changes the layout of the archive. I would expect command path1 path2 (where path1 is the thing to archive and path2 is the output) to always behave the same, but where you run it from matters. Here are some examples. (Output is pasted as a comment where relevant so you don’t need to run.)

mkdir -p user/app
touch user/file
touch user/app/file

echo '  from top'
tar czf archive user
tar tf archive
# user/
# user/app/
# user/file
# user/app/file

echo '  from inside'
cd user
tar czf ../archive .
cd ..
tar tf archive
# ./
# ./app/
# ./file
# ./app/file

Becasue of this weird behavior I prefer to use -C with it. Now what matters is if you want the top level folder or not. i.e., when you open it do you want it in a folder or directly in the working directory? If you do want the folder then use the first option. If not use the second.

echo '  with top level folder'
tar czf archive -C user app
tar tf archive
# app
# app/file

echo '  without top level folder'
tar czf archive -C user/app .
tar tf archive
# ./
# ./file

When using the second form you may want to do tar xf archive -C some_dir to make sure it goes into a directory named some_dir instead of directly into the working directory.