Manual: zsync

zsync(1)						File Transfer						    zsync(1)

NAME
       zsync - Partial/differential file download client over HTTP

SYNTAX
       zsync [ -u url ] [ -i inputfile ] [ -o outputfile ] [ { -s | -q } ] [ -k file.zsync ] [ -A hostname=username:password
       ] { filename | url }

       zsync -V

DESCRIPTION
       Downloads  a  file over HTTP. zsync uses a control file to determine whether any blocks in the file are already known
       to the downloader, and only downloads the new blocks.

       Either a filename or a URL can be given on the command line - this is the path of the control file for the  download,
       which normally has the name of the actual file to downlaod with .zsync appended. (To create this .zsync file you have
       to have a copy of the target file, so this file should be generated by the person providing the download).

       zsync  downloads	 to  your  current directory. It looks for any file in the directory of the same name as the file to
       download. If it finds one, it assumes that this is an earlier or incomplete version of the new file to download,	 and
       scans  this  file for any blocks that it can use to build the target file. (It also looks for a file of the same name
       with .part appended, so it will automatically find previously interrupted zsync downloads and reuse the data  already
       downloaded. If you know that the local file to use as input has a different name, you must use -i)

       zsync  retrieves	 the  rest  of the target file over HTTP. Once the download is finished, the old version (if the new
       file wants the same name) is moved aside (a .zs-old extension is appended). The modification time of the file is	 set
       to be the same as the remote source file (if specified in the .zsync).

OPTIONS
       -A hostname=username:password
	      Specifies a username and password to be used with the given hostname. -A can be used multiple times (with dif‐
	      ferent hostnames), in cases where e.g. the
	       .zsync  file  is on a different server from the download, or there are multiple download servers (there could
	      be different auth details for different servers - and zsync never assumes that your password should be sent to
	      a server other than the one named - otherwise redirects would be dangerous!).

       -i inputfile
	      Specifies (extra) input files. inputfile is scanned to identify blocks in common	with  the  target  file	 and
	      zsync uses any blocks found. Can be used multiple times.

       -k file.zsync
	      Indicates	 that  zsync should save the zsync file that it downloads, with the given filename. If that file al‐
	      ready exists, then zsync will make a conditional request to the web server, such that it will only download it
	      again if the server's copy is newer. zsync will append .part to the filename for storing it while it is  down‐
	      loading, and will only overwrite the main file once the download is done - and if the download is interrupted,
	      it will resume using the data in the .part file.

       -o outputfile
	      Override the default output file name.

       -q     Suppress the progress bar, download rate and ETA display.

       -s     Deprecated synonym for -q.

       -u url This  specifies  the  referring URL.  If you have a .zsync file locally (if you downloaded it separately, with
	      wget, say) and the .zsync file contains a relative URL, you need to specify where you got the .zsync file from
	      so that zsync knows which server and path to use for the rest of the download (this is analogous to  adding  a
	       to a downloaded web page to make the links work).

       -V     Prints the version of zsync.

FILES
ENVIRONMENT VARIABLES
       http_proxy
	      Should  be  the  [http://]hostname:port  for  your  web  proxy,  if  one	is required to access the target web
	      server(s).

EXAMPLES
       zsync	-i     /var/lib/apt/lists/server.debian.org_debian_dists_etch_main_binary-i386_Packages	    http://zsync.mo‐
       ria.org.uk/s/etch/Packages.zsync

AUTHORS
       Colin Phipps 

SEE ALSO
       zsyncmake(1)

Colin Phipps						    0.6.2						    zsync(1)