fsync [OPTIONS]... [FILES | DIRECTORIES]...
       fsync -s [-v[#]]


       Fsync is a Perl script which allows for file mirroring and synchroniza-
       tion. Since it is a single Perl script, setting up file synchronization
       on  a  new  machine  is simple. The perl script acts as both the client
       which the user interacts with and as a remote server, which is  started
       manually  or  by  the client, using a mechanism such as rsh or ssh. The
       program was written with slow modem connections in  mind.  Also,  fsync
       supports  the  concept  of  merging  differences from local/remote with
       hooks for tools to merge the trees.

       The  first  version  is  the  usual  client  invocation.  The  optional
       file/directory  arguments specify entities to be synchronized, overrid-
       ing the @fileList array variable. The second invocation starts fsync in
       server  mode. The server is usually automagically started on the remote
       host by the client. However, it can be started manually if desired.

       Normal use  usually  involves  setting  up  a  .fsyncrc  file  defining
       $remhost, @excludeList and @fileList. Most simple problems can be diag-
       nosed by setting $verbose=1 and looking at fsyncd.log file.

       Large files are copied efficiently- if a file has its end  changed  (or
       is partially copied), only the new parts are copied.

       If  fsync  receives the INT signal (often ctrl-C) while it is copying a
       file, it tries to gracefully shut down (it will  gracelessly  abort  on
       receiving  three  such signals). In the shutdown process, the partially
       copied file has its timestamp changed to 0 (Dec. 31, 1969) so that  the
       -n  flag will get the correct file during the next invocation of fsync.

       The only inherently Unix-specific aspect (which I can  currently  think
       of)  is  the  forward-slash  file separator character. Thus, porting to
       other operating systems should not  be  too  difficult--  if  there  is
       interest in this.

       The  optional  command-line  file/directory arguments are either inter-
       preted relative to the PWD environment  variable  or  should  be  fully
       qualified  (have  a  leading  /). The entries in the rc file are inter-
       preted relative to $rootdir.

       -bd  dir
              specify the directory to hold previous  versions  of  all  files
              which  are copied over. This sets the name on both the local and
              remote machines. If  this  string  is  ""  no  backup  is  made.
              Default: ~/.fsync-save

              evaluate file as the rc file (instead of ~/.fsyncrc).

       -fs,   follow symbolic links (copy objects that symlinks point to,  not
              the symlinks themselves).

       -ft,   follow top-level symbolic links explicitly specified on the com-
              mand line or in fileList. Convenient if there  are  a  only  few
              symlinks you wish to follow.

       -hf  file
              specify  the  file  which contains hash-save info. This sets the
              name on both the local and remote machines. See  the  documenta-
              tion  for  the  $hashSaveFile  variable below for information on
              multi-host syncing. Default: ~/.fsync-hashsave

       -L,    mirror the local side  to  the  remote.  This  option  adds  and
              updates  files,  directories,  hard and soft links on the remote
              machine such that they are  identical  to  those  on  the  local
              machine. When mirroring it may be desirable to set -bd "".

       -l  user
              specify user name on the remote host.

       -m     run  the merge command on all files which differ. The merge com-
              mand is specified by  the  $mergeCmd  variable.  Default:  emacs
              --eval  '(ediff \"Lfile\" \"Rfile\")', where Lfile and Rfile are
              replaced by the names of the local and remote files.

       -n     Overwrite older files with their newer counterpart. Fsync checks
              whether the older file has been modified since the previous time
              fsync was run and, if so, prompts for user intervention  instead
              of performing the copy.

       -nd    Do  not  set  the date/time when a file is copied. i.e. make the
              time value that corresponding to when fsync copied the file.

       -np    Do not change permissions when a file is overwritten.

       -ns    Do not stop server when quitting client. The connection informa-
              tion (host, port, password) are stored in a file with name given
              by $passcodeFilename. When starting, the client looks  for  this
              file  and  attempts  to use this connection if the host and port

       -own   Synchronize the uid and gid of files and directories.  Does  not
              yet work for symlinks.

       -p  port,
              specify  the  port  used  for fsync communications. A value of 0
              causes fsync to use the underlying rsh (or ssh)  connection  for

       -rr  root dir,
              specify the root directory used on the remote machine.

       -S     set Skip Mode. It this is specified, no interactive prompts will
              be  issued-  the  default option will always be taken. So, if -S
              appears alone on the command line, fsync will copy no files, but
              will  report differences. On the other hand, if the command line
              has -S -n -c, all files smaller than $promptFilesize  and  whose
              older versions have not been modified  will be copied.

       -V     display version

              Verbose. Print informational messages. If no digit is specified,
              verbosity is set to 1, larger numbers result in more output.

   User configurable variables
       These can be set in the rc file. The default value is bracketed.

              name of the log file containing error and informational messages
              from processeson running the server. [ ".fsyncd.log" ]

              the verbosity level. [ 0 ]

        $port The  port  which fsync uses. This should be set to something not
              in use. A value of 0 will cause fsync to use  the  the  rsh  (or
              ssh) connection for communication. [ 9005 ]

        $rsh  The  name  of  the  program  used  by the client to start up the
              server. Instances of the strings REMHOST, PROXYHOST,  PORT,  and
              PROXYPORT  are replaced by the name of the remote host, the name
              of the proxy host, the remote port and the proxy  port,  respec-
              tively. If you manually start the server, set $rsh to "". [ "rsh
              -l $remuser REMHOST" ]

              command to run to merge files  which  differ.  [  "emacs  --eval
              '(ediff \"Lfile\" \"Rfile\")'" ]

              command  to  run  to display the differences between files which
              differ. [ "diff Lfile Rfile" ]

              command to execute on the remote host to fire up the server (the
              -s argument is added). [ "bin/fsync" ]

              name of the root directory on the remote host. [ ~ ]
              name  of the hash-save file on the local host. [ "~/.fsync-hash-
              save" ] If you are synchronizing  filesystems  between  multiple
              hosts  (more  than two), it is suggested that multiple hash-save
              files be used (so that fsync understands whether a file has been
              modified).  To aid in this, fsync can employ a filesystem unique
              id (fsuid): if you include the substring "FSUID"  in  $hashSave-
              File, it is replaced by the fsuid. Hence, setting $hashSaveFile=
              ".fsync-hashsave-FSUID", will result in safe  fsyncing  with  -n
              flag between multiple hosts.

              name  of  the  hash-save file on the remote host. If this is not
              set, it defaults to that on the local host.

              name of the backup directory on the local host.  See  the  entry
              for the -bd option.

              name  of  the  backup directory on the remote host. If it is not
              set, it defaults to the value of $backupDir.

              name of the external checksum program. It  is  highly  suggested
              that  this  program  be  in the user's path - or specified abso-
              lutely. If fsync finds this program and verifies that it  works,
              it will greatly speed the initial recursion of directory hierar-
              chies. Note that it must use the algorithm of the standard  Unix
              cksum program.  [ cksum ]

              size  in  bytes  above  which the user is prompted before a copy
              occurs. This helps prevent inadvertent copying of huge files.  [
              1024*1024 ]

              size (in bytes) of in-memory file buffer used for copying files.
              [ 100000 ]

              the number of attempts  the  client  makes  to  connect  to  the
              server. [ 50 ]

              The interval in seconds between connection attempts. [ 2 ]

              an array of entries (directories, symlinks, and files, including
              hard links) to synchronize.  These  are  specified  relative  to
              $rootDir  on  the  local machine and relative to $rem_rootdir on
              the remote machine.

              whether to follow symbolic links (see -fs above) [0].

              whether  to follow top-level symbolic links (see -ft above) [0].


       The tilde abbreviation for matching home directories is not implemented
       for  entries in the rc file. As a workaround for $f = "~/blah"; use: $f
       = $ENV{"HOME"} . "/blah";
       Signal handling does not work correctly with $port=0.
       Misbehavior if a symlink is followed outside of the rootDir  hierarchy:
       symlinks  to  directories will not be created. However, synchronization
       of files and directories should work properly.


       Written by <>
       communication over the rsh/ssh medium and -ns functionality contributed
       by Patrick Ohly <>.
       -fs functionality contributed by Alexey Nogin <>.
       -own functionality from Jon Hittner <>.
       rpm spec file from David Slimp <>.
       News, updates and documentation: visit


       Copyright (C) 1999-2002 Charles D. Schwieters
       This is free software; see the source for copying conditions.  There is
       NO warranty; not even for MERCHANTABILITY or FITNESS FOR  A  PARTICULAR

2002"                              November                           FSYNC(1)

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