Archiving and Compressing Files

30 Jan 2021

tar - Archiving

To archive files you will use tar. tar combines many files and directories into one archive file that usually ends in “tar” however this is only by convention. This archive can be a regular file or a device, such as a tape archive. This is where the name of tar comes from: tape archive.

####################
# Basic tar options
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c - Create

v - Verbose

f <file_name> - File option, next argument after 'f' flag should be the name of the archive file. Use with the rest of the options to specify a specific archive file.

t - Table of contents mode, use to list contents of archive file 

x - Extract mode

p - Preserve permissions, tar sets the permissions **after** checking the entire archive

z - Filter the archive through gzip, when used with Extract it will decompress, with Create, it will compress

-C - Specify different directory to extract to

--same-owner - Keep the same ownership as exists in the archive, other wise it defaults to the user running the tar command

Examples

Creating a tar archive $ tar cvf archive.tar file1 file2

Extracting an archive $ tar xvf archive.tar

Extracting an archive to a different directory $ tar xvf archive.tar -C /path/to/dir

See what is inside of archive $ tar tvf archive.tar

gzip - Compressing

Standard Unix compression program is gzip (GNU Zip). Files ending in .gz are GNU Zip archives.

To use:

• Compress by running gzip file
• Uncompress by running gunzip file.gz

Dealing with .tar.gz files

This is a common filetype that you will encounter on Linux systems. You will first have to uncompress (get rid of the .gz) and then extract the archive (the .tar part).

This is the long way and you should build up the muscle memory of this first:

$ gunzip file.tar.gz

$ tar xvf file.tar

After getting tired of the above, shortcuts can be done numerous ways.

zcat is the same as using gunzip -dc.

$ gunzip -dc archive.tar.gz | tar xvf - -C random_dir/

$ zcat archive.tar.gz | tar xvf - -C random_dir/

tar comes with a shortcut for zcat. You can use the “z” flag.

Shortcuts for creating+compressing and extracting+decompressing:

$ tar zcvf archive.tar.gz file1 file2

$ tar zxcf archive.tar.gz -C /path/to/dir/

Quick note on zip/unzip

To interact with .zip files, you will need zip and unzip on the Linux machine.

Create a zip file

$ zip archive file1 file2

Unzip a zip file $ unzip archive.zip

Unzip a zip file to a specific directory $ unzip archive.zip -d /path/to/dir

List contents of a zip file $ zip -l archive.zip