Extract and Compress 7z files in command line

7-Zip is a file archiver with a high compression ratio. The file compressed by 7-Zip has an extension ”.7z”. Here is a list of main features of 7-Zip, which is from its official website:

High compression ratio in 7z format with LZMA and LZMA2 compression

Supported formats:

Packing / unpacking: 7z, XZ, BZIP2, GZIP, TAR, ZIP and WIM

Unpacking only: AR, ARJ, CAB, CHM, CPIO, CramFS, DMG, EXT, FAT, GPT, HFS, IHEX, ISO, LZH, LZMA, MBR, MSI, NSIS, NTFS, QCOW2, RAR, RPM, SquashFS, UDF, UEFI, VDI, VHD, VMDK, WIM, XAR and Z.

For ZIP and GZIP formats, 7-Zip provides a compression ratio that is 2-10 % better than the ratio provided by PKZip and WinZip

Strong AES-256 encryption in 7z and ZIP formats

Self-extracting capability for 7z format

Integration with Windows Shell

Powerful File Manager

Powerful command line version

Plugin for FAR Manager

Localizations for 87 languages

To use 7z in command line we need to install it first.
Installation of 7-Zip on CentOS/RHEL:

# sudo yum info p7zip

Installation of 7-Zip on Ubuntu/Debian:

# sudo apt-get install p7zip-full

To extract / Create an 7z file:

$ 7z x archive.7z

To create a compressed file with 7-Zip:

$ 7za a -t7z ../archive.7z *

The command compresses all the files in currently directory, and generates a compressed file in upper directory. Note that the command we use is “7za”.

To remove a single file from an archive
We can also remove a single file from an archive with “d”. This is more useful when you do not have a solid archive.

7z d archive.zip *.bak -r

Then all the matched files (which has extension “.bak”) will be remove from archive, and “-r” traverses all subdirectories.

To create an encrypted file with 7-Zip

This can be done by the switch p. We use the “-p” switch, which refers to the word “password”. This is really helpful when security and encryption is involved. You can specify a password on the command line.

$ 7za a pw.7z *.txt -pYOURSECRET

This command add all the *.txt files to destination archive, and specify the password “YOURSECRET”

To exclude certain files in compressing
Sometimes we want to manually exclude certain files. Use the -x switch, followed immediately with an exclamation mark and then the filename. If you want to exclude “file.txt”, use the switch “-x!file.txt”. Please include the hyphen and exclamation.