7-ZIP – Compression program.

Usage:

7za  [...] <archive_name> [<file_names>...] [<@listfiles...>]

Solid mode:

Solid mode allows to compress files as one block when turn on. This means that updating single compressed file will not be possible.

-ms=on - Enable solid mode. All files are compressed as one (unable to update, and only for 7z format). Default behaviour. 
-ms=off - Disable solid mode.

Commands:

a - Archive, add. Puts files into an archive. (7za a -t7z files.7z *.txt)
d - Delete. Deletes file from an archive. (7za d archive.zip *.bak -r)
e - Extract. Extracts archive in current directory.
x - Extract with directory structures preserve. Full paths are stored.
l - List. Shows file listing and description of an archive. (7za l files.7z)
t - Tests integrity. Test used for diagnostics.
u - Update. Used to update files in archive without decompressing and compressing whole archive. (7z u archive.zip *.doc)
m - Method. Specifies the compression method.
    Switch -mx0: Don't compress at all. This is called "copy mode."
    Switch -mx1: Low compression. This is called "fastest" mode.
    Switch -mx3: Fast compression mode. Will automatically set various parameters.
    Switch -mx5: Same as above, but "normal."
    Switch -mx7: This means "maximum" compression.
    Switch -mx9: This means "ultra" compression. You probably want to use this.
t - Type. Specifies archive type that you want to create.
    Switch: -t7z Format: 7Z
    Switch: -tgzip Format: GZIP
    Switch: -tzip Format: ZIP
    Switch: -tbzip2 Format: BZIP2
    Switch: -ttar Format: TAR
    Switch: -tiso Format: ISO
    Switch: -tudf Format: UDF
r - Recursive. Look to sub-directories when wildcard used.

Switches:

-y - Stops prompting. Automatically answers "Yes" to all questions. 
-ms=on - Enable solid mode. All files are compressed as one (unable to update, and olny for 7z format). Default behaviour. 
-ms=off - Disable solid mode. 
-o - Output. (7z x archive.zip -oC:Doc) 
-p - Password. (7za a pw.7z *.txt -pSECRET) 
-mhe - Encrypts headers. File names are not visible until decryption. 
-ssc - Specify case-sensitive (Windows default: insensitive, Linux default: sensitive). 
-ssw - Compress locked files. 
-sw - Specify working directory. 
-so - Redirect output to standard stream. 

Sources:

http://www.dotnetperls.com/7-zip-examples
http://www.7-zip.org/