Tar cheatsheet

Tape ARchive (TAR) is an classic file format that is used to archive files. Note that it does not compress the files to save space. Rather it is only for convenience of handling a single archive file instead of dealing with thousands of files. I typically use it to quickly move directories containing large number of small files.

Note that tar is an incredibly old Unix tool and confusingly accepts arguments in 3 styles: traditional (without dashes), UNIX short-option (single dash) and GNU long-option (double dash). I abhor using the traditional style (which is quite popular online) since it is un-UNIX and instead use the short-option style for interactive use (and below) and use the long-option style in scripts.

• To archive some files into a tape archive file specify the archive name first and follow with the files to archive:

$ tar -cf foobar.tar foobar1.txt foobar2.txt

• To archive a directory named foobar:

$ tar -cf foobar.tar foobar

• To archive and output the tar contents to the terminal use - as the output filename. This is typically used to redirect the tar output or to process the tar output with other tools:

$ tar -cf - foobar1.txt foobar2.txt > foobar.tar

$ tar -cf - foobar1.txt foobar2.txt | wc

• To sort the files before tarring:

$ tar --sort="name" -cf foobar.tar foobar

Apparently, this can sometimes result in better compression.

• To view the list of files being archived specify the verbose option -v:

$ tar -cvf foobar.tar foobar

• To extract or untar an archive to the current directory:

$ tar -xf foobar.tar

• It is not possible to delete a file from a tarfile. But files can be skipped during extract:

$ tar -xf foobar.tar --exclude exclude1

• To extract to a specific directory, create it first and then specify it:

$ mkdir foobar
$ tar -xf haha.tar --directory foobar
$ tar -xf haha.tar -C foobar

• To extract but chop off one or more base directories from the relative file paths being extracted, use the --strip-components option:

$ tar -xf haha.tar
Writes out foo/bar/rocky/zoo.py

$ tar -xf haha.tar --strip-components 2
Writes out rocky/zoo.py

• To view list of files during untar:

$ tar -xvf foobar.tar

• To list the contents of an archive file:

$ tar -tvf foobar.tar

• To archive and encrypt a tar file, we archive the contents and redirect the contents to openssl for encryption:

$ tar -cf - foobar1.txt foobar2.txt | openssl enc -e -aes256 -out foobar.tar

You will be asked to enter the password to use to encrypt the contents.

• To decrypt and untar the contents of an encrypted tar file to the current directory:

$ openssl enc -d -aes256 -in foobar.tar | tar -x

You will be asked to enter the password to decrypt the contents.

References:

• tar manpage
• openssl enc manpage

Tried with: Tar 1.27.1 and Ubuntu 14.04