SFX files definition
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Self-extracting
archives
(briefly referred as SFX files) are computer executable programs
containing
both an (usually compressed) archive of files and the routines needed
to extract the content (SFX module), usually packed as Microsoft
Windows EXE executable file. |
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Use of SFX
archives
WinRar, WinZip, 7-Zip, PeaZip, and other file archiver software are
capable of creating self extracting archives, usually employing 7Z,
RAR and ZIP compression
for the archival part - learn more: what
is a compressed archive file -
and minimal sfx modules
suitable for basic tasks of deployment of content as autonomous
packages, not needing external dedicated decompression software
and capable of
auto-unpacking themselves.
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While an
auto-extracting archive is potentially a simple, basic form of
installer, most software for creation of installation packages extends
the idea further providing
formats capable of advanced scripting features to generate more complex
and flexible
autoextraction modules to unpack the content and perform other related
operations, suc as conditional extraction of appropriate data,
automatic output path detection, registration of shared files,
interaction with registry etc. |
SFX archives:
advantages and disadvantages
Principle behind self extracting archives is providing the end user of
the appropriate extraction
executable instructions without the need of installing any software,
which brings those advantages over non self extracting archives:
- content and extraction tools are passed as atomic
information
- in order to extract the content, end user needs to
run only a simple subset of instructions, through a minimal user
interface requiring little or no feedback, rather than having to
install and learn to operate a full general purpose archive manager
software
Drawbacks of self extracting archives are:
- being the
extraction module embedded in the archive itself, it represents an
overhead (usually some 10s or 100s of KB), which makes it a noticeable
disadvantage in
the case of small archives
- the sfx archive can be executed only on operating
system platforms capable to run the sfx module - it can still be
operated as a standard archive on other platforms, if suitable software
is available
- being the self extracting archive an
executable file, some file sharing platforms - cloud service
providers, e-mail servers - may consider it a security risk and block
the file, preventing it to reach the intended end users.
Max size of a
self-extracting
archive
On Windows platform .exe executables must be smaller than 2 GB
(even PE and 64 bit Windows binaries).
Consequently, SFX format
cannot be used to create a valid sfx archives larger than 2 GB.
A SFX file larger than 2 GB will still be readable as archive, suing an
external archive manager tool - basically, it is plainly an archive
with SFX executable module attached - but Windows will not be able to
run the SFX module because the .exe file is larger than the maximum
allowed size of 2 GB.
Add files to SFX
archive in PeaZip
To create a SFX
archive with PeaZip, select desired files and folders and click "Add"
button for archive creation screen.
PeaZip can create self extracting 7Z
files and, alternatively, self extracting archives in ARC format:
supported SFX formats can be
selected directly in archive format dropdown menu,
simply selecting "Self-extracting 7Z"
or "Self-extracting ARC"
entries.
In "Advanced" tab of archive creation screen it is possible to select
one of the available alternative SFX modules, which is the binary
routine that will be embedded in
the archive and which will handle the extraction of the content on
recipient's machine without requiring external software.
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Recipient will not need a
suitable
unarchiver application to open self-extracting files as the sfx module
itself is autonomous
for extraction of package content.
Please note, anyway, recipient will at least need the right to execute
binary files (the sfx module) on the target system to proceed with
(auto)extraction of the SFX archive.
Alternatively some archive
managers, as PeaZip, can try to open
arbitrary file types as archives
(including most sfx packages) for custom content extraction without
running the sfx module - which is recommended over running the files as
binary if the source of the archive is unknown.
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Encrypting a self
extracting archive
To add a password to archive to
prevent unauthorized decompression of the
self-extracting archive, click on the padlock icon button "Enter
password / keyfile" - also the encryption options are customizable in
"Advanced" tab.
Please note that when
a
self-extracting archive is created, only the password (if provided)
will be used for encrypting the data, and only the password will be
needed to
extract & decrypt it, this because available SFX modules
does not support two factor authentication
and would
be unable to parse the keyfile, failing decryption.
Custom SFX modules
Custom sfx modules
with different sets of features and user interaction
interfaces are available in PeaZip add-ons section Custom SFX
modules.
Read more: Self-extracting
archives Wikipedia
page
Synopsis: What are self extracting archives, what are
advantages and disadvantages in using sfx files. Create sfx files with PeaZip free archiver
software. How to create self
extracting archives, and work with sfx archives.
Topics: sfx self
extractiong archives
PeaZip > FAQ >
How to create Self Extracting Archives (SFX)
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