Escape potential tarbombs

atb() { l=$(tar tf $1); if [ $(echo "$l" | wc -l) -eq $(echo "$l" | grep $(echo "$l" | head -n1) | wc -l) ]; then tar xf $1; else mkdir ${1%.tar.gz} && tar xf $1 -C ${1%.tar.gz}; fi ;}
This Anti-TarBomb function makes it easy to unpack a .tar.gz without worrying about the possibility that it will "explode" in your current directory. I've usually always created a temporary folder in which I extracted the tarball first, but I got tired of having to reorganize the files afterwards. Just add this function to your .zshrc / .bashrc and use it like this; atb arch1.tar.gz and it will create a folder for the extracted files, if they aren't already in a single folder. This only works for .tar.gz, but it's very easy to edit the function to suit your needs, if you want to extract .tgz, .tar.bz2 or just .tar. More info about tarbombs at http://www.linfo.org/tarbomb.html Tested in zsh and bash. UPDATE: This function works for .tar.gz, .tar.bz2, .tgz, .tbz and .tar in zsh (not working in bash): atb() { l=$(tar tf $1); if [ $(echo "$l" | wc -l) -eq $(echo "$l" | grep $(echo "$l" | head -n1) | wc -l) ]; then tar xf $1; else mkdir ${1%.t(ar.gz||ar.bz2||gz||bz||ar)} && tar xf $1 -C ${1%.t(ar.gz||ar.bz2||gz||bz||ar)}; fi ;} UPDATE2: From the comments; bepaald came with a variant that works for .tar.gz, .tar.bz2, .tgz, .tbz and .tar in bash: atb() {shopt -s extglob ; l=$(tar tf $1); if [ $(echo "$l" | wc -l) -eq $(echo "$l" | grep $(echo "$l" | head -n1) | wc -l) ]; then tar xf $1; else mkdir ${1%.t@(ar.gz|ar.bz2|gz|bz|ar)} && tar xf $1 -C ${1%.t@(ar.gz|ar.bz2|gz|bz|ar)}; fi ; shopt -u extglob}
Sample Output
$ tar tf arch1.tar.gz                                                                       
file1
file2
file3

$ tar tf arch2.tar.gz                                                                       
dir1/                
dir1/file2
dir1/file3
dir1/file1

$ atb arch1.tar.gz

$ atb arch2.tar.gz

$ tree
.
|-- arch1
|   |-- file1
|   |-- file2
|   `-- file3
|-- arch1.tar.gz
|-- arch2.tar.gz
`-- dir1
    |-- file1
    |-- file2
    `-- file3

2 directories, 8 files

10
By: elfreak
2010-10-16 05:50:32

What Others Think

Very interesting. Note, with modern versions of GNU Tar you don't need the 'z' to unpack compressed tars. These will work: tar xf jim.tar.gz tar xf bob.tar.bz2
flatcap · 418 weeks ago
Thank you, I will update the command soon :)
elfreak · 418 weeks ago
I have now added a function that extracts .tar.gz, .tar.bz2, .tgz, .tbz and .tar, but this only works in zsh. Apparently bash does not like ${1%.t(ar.gz||ar.bz2||gz||bz||ar)} If anyone knows how to do this in bash (without sed/awk/etc.) please tell me :)
elfreak · 417 weeks and 6 days ago
In bash this is only possible with extended globbing enabled. You'd have to do something like this: atb() {shopt -s extglob ; l=$(tar tf $1); if [ $(echo "$l" | wc -l) -eq $(echo "$l" | grep $(echo "$l" | head -n1) | wc -l) ]; then tar xf $1; else mkdir ${1%.t@(ar.gz|ar.bz2|gz|bz|ar)} && tar xf $1 -C ${1%.t@(ar.gz|ar.bz2|gz|bz|ar)}; fi ; shopt -u extglob}
bepaald · 417 weeks and 3 days ago
Ah, OK, thanks
elfreak · 417 weeks and 3 days ago

What do you think?

Any thoughts on this command? Does it work on your machine? Can you do the same thing with only 14 characters?

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