Content-type: text/html Man page of filesync


Section: User Commands (1)
Updated: 6 Nov 2000
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filesync - synchronize ordinary, directory or special files  


filesync [-aehmnqvy] [-o src | dst] [-f src | dst | old | new] [-r directory...]

filesync [-aehmnqvy] -s source-dir -d dest-dir filename...  


The filesync utility synchronizes files between multiple computer systems, typically a server and a portable computer. filesync synchronizes ordinary, directory or special files. Although intended for use on nomadic systems, filesync is useful for backup and file replication on more permanently connected systems.

If files are synchronized between systems, the corresponding files on each of the systems are identical. Changing a file on one or both of the systems causes the files to become different (not synchronized). In order to make the files identical again, the differences between the files must be reconciled. See Reconciling and Synchronizing Files for specific details about how filesync reconciles and synchronizes files.

There are two forms of the filesync command. The first form of filesync is invoked without file arguments. This form of filesync reconciles differences between the files and systems specified in the $HOME/.packingrules file. $HOME/.packingrules is a packing rules list for filesync and cachefspack, and contains a list of files to be kept synchronized. See packingrules(4) and cachefspack(1M).

The second form of filesync copies specific files from a directory on the source system to a directory on the destination system. In addition, this form of filesync adds the file or files specified as arguments (filename) to $HOME/.packingrules. See -s and -d for information about specifying directories on source and destination systems. See OPERANDS for details about specifying file (filename) arguments.

Multiple filesync commands are cumulative (that is, the specified files are added to the already existing packing rules file list). See Multiple filesync Commands.  

Reconciling and Synchronizing Files

filesync synchronizes files between computer systems by performing the following two tasks:

1. filesync examines the directories and files specified in the packing rules file on both systems, and determines whether or not they are identical. Any file that differs requires reconciliation.

filesync also maintains a baseline summary in the $HOME/.filesync-base file for all of the files that are being monitored. This file lists the names, types, and sizes of all files as of the last reconciliation.

2. Based on the information contained in the baseline file and the specified options (see Resolving filesync Conflicts), filesync determines which of the various copies is the correct one, and makes the corresponding changes to the other system. Once this has been done, the two copies are, again, identical (synchronized).

If a source file has changed and the destination file has not, the changes on the source system are propagated to the destination system. If a destination file has changed and the corresponding source file has not, the changes on the destination file are propagated to the source system. If both systems have changed (and the files are not still identical) a warning message will be printed out, asking the user to resolve the conflict manually. See Resolving filesync Conflicts.


Resolving filesync Conflicts

In cases where files on both sides have changed, filesync attempts to determine which version should be chosen. If filesync cannot automatically determine which version should be selected, it prints out a warning message and leaves the two incompatible versions of the file unreconciled.

In these cases, you must either resolve the differences manually, or tell filesync how to choose which file should win. Use the -o and -f options to tell filesync how to resolve conflicts (see OPTIONS).

Alternatively, for each conflicting file, you can examine the two versions, determine which one should be kept, and manually bring the two versions into agreement (by copying, deleting, or changing the ownership or protection to be correct). You can then re-run filesync to see whether or not any other conflicts remain.  

Packing Rules File

The packing rules file $HOME/.packingrules contains a list of files to be kept synchronized. The syntax of this file is described in packingrules(4).

The $HOME/.packingrules file is automatically created if users invoke filesync with filename arguments. By using filesync options, users
 can augment the packing rules in $HOME/.packingrules.

Many users choose to create the packing rules file manually and edit it by hand. Users can edit $HOME/.packingrules (using any editor) to permanently change the $HOME/.packingrules file, or to gain access to more powerful options that are not available from the command line (such as IGNORE commands). It is much easier to enter complex wildcard expressions by editing the $HOME/.packingrules file.  

Baseline File

$HOME/.filesync-base is the filesync baseline summary file. filesync uses the information in $HOME/.filesync-base to identify the differences between files during the reconciliation and synchronization process. Users do not create or edit the baseline file. It is created automatically by filesync and records the last known state of agreement between all of the files being maintained.  

Multiple filesync Commands

Over a period of time, the set of files you want to keep synchronized can change. It is common, for instance, to want to keep files pertaining to only a few active projects on your notebook. If you continue to keep files associated with every project you have ever worked on synchronized, your notebook's disk will fill up with old files. Each filesync command will waste a lot of time updating files you no longer care about.

If you delete the files from your notebook, filesync will want to perform the corresponding deletes on the server, which would not be what you wanted. Rather, you would like a way to tell filesync to stop synchronizing some of the files. There are two ways to do this:

1. Edit $HOME/.packingrules. Delete the rules for the files that you want to delete.

2. Delete $HOME/.packingrules. Use the filesync command to specify the files that you want synchronized.

Either way works, and you can choose the one that seems easiest to you. For minor changes, it is probably easier to just edit $HOME/.packingrules. For major changes it is probably easier to start from scratch.

Once filesync is no longer synchronizing a set of files, you can delete them from your notebook without having any effect on the server.  

Nomadic Machines

When using filesync to keep files synchronized between nomadic machines and a server, store the packing rules and baseline files on the nomadic machines, not the server. If, when logged into your notebook, the HOME environment variable does not normally point to a directory on your notebook, you can use the FILESYNC environment variable to specify an alternate location for the packing rules and baseline files.

Each nomadic machine should carry its own packing rules and baseline file. Incorrect file synchronization can result if a server carries a baseline file and multiple nomadic machines attempt to reconcile against the server's baseline file. In this case, a nomadic machine could be using a baseline file that does not accurately describe the state of its files. This might result in incorrect reconciliations.

To safeguard against the dangers associated with a single baseline file being shared by more than two machines, filesync adds a default rule to each new packing rules file. This default rule prevents the packing rules and baseline files from being copied.  


The following options are supported:


Force the checking of Access Control Lists (ACLs ) and attempt to make them agree for all new and changed files. If it is not possible to set the ACL for a particular file, filesync stops ACL synchronization for that file.

Some file systems do not support ACLs . It is not possible to synchronize ACLs between file systems that support ACLs and those that do not; attempting to do so will result in numerous error messages.

-d dest-dir

Specify the directory on the destination system into which filename is to be copied. Use with the -s source-dir option and the filename operand. See -s and OPERANDS.


Flag all differences. It may not be possible to resolve all conflicts involving modes and ownership (unless filesync is being run with root privileges). If you cannot change the ownership or protections on a file, filesync will normally ignore conflicts in ownership and protection. If you specify the -e (everything must agree) flag, however, filesync will flag these differences.

-f src | dst | old | new

The -f option tells filesync how to resolve conflicting changes. If a file has been changed on both systems, and an -f option has been specified, filesync will retain the changes made on the favored system and discard the changes made on the unfavored system.

Specify -f src to favor the source-system file. Specify -f dst to favor the destination-system file. Specify -f old to favor the older version of the file. Specify -f new to favor the newer version of the file.

It is possible to specify the -f and -o options in combination if they both specify the same preference (src and dst). If
 -f and  -o conflict, the  -f option is ignored. See the -o option description.


Halt on error. Normally, if filesync encounters a read or write error while copying files, it notes the error and the program continues, in an attempt to reconcile other files. If the -h option is specified, filesync will immediately halt when one of these errors occurs and will not try to process any more files.


Ensure that both copies of the file have the same modification time. The modification time for newly copied files is set to the time of reconciliation by default. File changes are ordered by increasing modification times so that the propagated files have the same relative modification time ordering as the original changes. Users should be warned that there is usually some time skew between any two systems, and transferring modification times from one system to another can occasionally produce strange results.

There are instances in which using filesync to update some (but not all) files in a directory will confuse the make program. If, for instance, filesync is keeping .c files synchronized, but ignoring .o files, a changed .c file may show up with a modification time prior to a .o file that was built from a prior version of the .c file.


Do not really make the changes. If the -n option is specified, filesync determines what changes have been made to files, and what reconciliations are required and displays this information on the standard output. No changes are made to files, including the packing rules file.

Specifying both the -n and -o options causes filesync to analyze the prevailing system and report the changes that have been made on that system. Using -n and -o in combination is useful if your machine is disconnected (and you cannot access the server) but you want to know what changes have been made on the local machine. See the -o option description.

-o src | dst

The -o option forces a one-way reconciliation, favoring either the source system (src) or destination system (dst).

Specify -o src to propagate changes only from the source system to the destination system. Changes made on the destination system are ignored. filesync aborts if it cannot access a source or destination directory.

Specify -o dst to propagate changes only from the destination system to the source system. Changes made on the source system are ignored. filesync aborts if it cannot access a source or destination directory.

Specifying -n with the -o option causes filesync to analyze the prevailing system and reports on what changes have been made on that system. Using -n and -o in combination is useful if a machine is disconnected (and there is no access to the server), but you want to know what changes have been made on the local machine. See the -n option description.

It is possible to specify the -o and -f options in combination if they both specify the same preference (src or dst). If -o and -f options conflict, the -f option will be ignored. See the -f option description.


Suppress the standard filesync messages that describe each reconciliation action as it is performed.

The standard filesync message describes each reconciliation action in the form of a UNIX shell command (for example, mv, ln, cp, rm, chmod, chown, chgrp, setfacl, and so forth).

-r directory

Limit the reconciliation to directory. Specify multiple directories with multiple -r specifications.

-s source-dir

Specify the directory on the source system from which the filename to be copied is located. Use with the -d dest-dir option and the filename operand. See the -d option description and OPERANDS.


Display additional information about each file comparison as it is made on the standard output.


Bypass safety check prompts. Nomadic machines occasionally move between domains, and many of the files on which filesync operates are expected to be accessed by NFS. There is a danger that someday filesync will be asked to reconcile local changes against the wrong file system or server. This could result in a large number of inappropriate copies and deletions. To prevent such a mishap, filesync performs a few safety checks prior to reconciliation. If large numbers of files are likely to be deleted, or if high level directories have changed their I-node numbers, filesync prompts for a confirmation before reconciliation. If you know that this is likely, and do not want to be prompted, use the -y (yes) option to automatically confirm these prompts.



The following operands are supported:

filename The name of the ordinary file, directory, symbolic link, or special file in the specified source directory (source-dir) to be synchronized. Specify multiple files by separating each filename by spaces. Use the filename operand with the -s and -d options. See OPTIONS.

If filename is an ordinary file, that ordinary file will be replicated (with the same filename) in the specified destination directory (dest-dir).

If filename is a directory, that directory and all of the files and subdirectories under it will be replicated (recursively) in the specified destination directory (dest-dir).

If filename is a symbolic link, a copy of that symbolic link will be replicated in the specified destination directory (dest-dir).

If filename is a special file, a special file with the same major or minor device numbers will be replicated in the specified destination directory. (dest-dir). Only super-users can use filesync to create special files.

Files created in the destination directory (dest-dir) will have the same owner, group and other permissions as the files in the source directory.

If filename contains escaped shell wildcard characters, the wildcard characters are stored in $HOME/.packingrules and evaluated each time filesync is run.

For example, the following would make sure that the two specified files, currently in $RHOME, were replicated in $HOME:

filesync -s $RHOME  -d $HOME a.c b.c


The following example would ensure that all of the *.c files in $RHOME were replicated in $HOME, even if those files were not created until later.

filesync -s $RHOME -d $HOME '*.c'


If any of the destination files already exist, filesync ensures that they are identical and issues warnings if they are not.

Once files have been copied, the distinction between the source and destination is a relatively arbitrary one (except for its use in the -o and -f switches).



FILESYNC Specifies the default location of the filesync packing rules and baseline files. The default value for this variable is $HOME. The suffixes .packingrules and .filesync-base will be appended to form the names of the packing rules and baseline files.

LC_MESSAGES Determines how diagnostic and informative messages are presented. In the "C" locale, the messages are presented in the default form found in the program itself (in most cases, U.S. English).



Normally, if all files are already up-to-date, or if all files were successfully reconciled, filesync will exit with a status of 0. However, if either the -n option was specified or any errors occurred, the exit status will be the logical OR of the following:

0 No conflicts, all files up to date.

1 Some resolvable conflicts.

2 Some conflicts requiring manual resolution.

4 Some specified files did not exist.

8 Insufficient permission for some files.

16 Errors accessing packing rules or baseline file.

32 Invalid arguments.

64 Unable to access either or both of the specified src or dst directories.

128 Miscellaneous other failures.



$HOME/.packingrules list of files to be kept synchronized

$HOME/.filesync-base baseline summary file



See attributes(5) for descriptions of the following attributes:




cachefspack(1M), packingrules(4), attributes(5)



Reconciling and Synchronizing Files
Resolving filesync Conflicts
Packing Rules File
Baseline File
Multiple filesync Commands
Nomadic Machines

This document was created by man2html, using the manual pages.
Time: 02:39:29 GMT, October 02, 2010