PRESERVE(1M)        RISC/os Reference Manual         PRESERVE(1M)



NAME
     preserve - save selected release files for update installa-
          tion

SYNTAX
     preserve [ -r | -s ] version

DESCRIPTION
     preserve is used to save a selected list of files on a sys-
     tem receiving an update of a software package. It is usually
     used along with findmods (see findmods(1M)) to insure that
     no local modifications of files present in the update will
     be overwritten when installing the release.

     Exactly one of the options -s or -r must be used. The -s
     (save) option is used before the update files are written to
     the target system. -r (restore) is used after the update
     files have been written.  The argument version identifies
     the version of the package being installed. The version will
     be used as a tag to identify files saved by preserve when
     installing this version of the software package.

     The actions performed by preserve are determined by the
     option flag used, and a newline separated list of pathnames
     provided on its standard input. The pathnames are given
     relative to the root directory of the package. This is the
     same convention as used by comply for pathnames in the
     software bill of materials files (``bomfile''s; see
     comply(1M)) for a description of the pathname format).

     The input to preserve is usually a concatenation of the out-
     put from findmods and a default list naming the set of files
     in the package which are expected to be modified locally.
     (For example, in the RISC/os package, this would include
     /etc/passwd, etc/hosts, and so on).

     By providing a default list, a safer update installation can
     be performed on a system where a valid /etc/installlog file
     is not present.  (See installlog(4) for a description of
     /etc/installlog).

     Each pathname may be followed by one of three option flags
     which modifies preserve's behavior when processing that
     file. The options are:

     (no flags)
          All files named by findmods take this default action.
          The file pathname present on the target system will be
          saved as ``pathname:version:''  before the file from
          the release is written to the target system.

     -k  (``keep'')



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          The file pathname present on the target system prior to
          the installation of the update should be kept as path-
          name.  The file read from the update will be saved as
          ``pathname:version+''.

     -u  (``use update'')
          The use of the file supplied on the update is forced.
          The file pathname present on the target system will be
          saved as ``pathname/:version:''  before the file from
          the release is written to the target system. This
          option takes precedence over the others. This is impor-
          tant for files where failure to use the new version (or
          a converted copy of the local version) would render the
          system or software package inoperative.

     -d   The file pathname is no longer a part of this software
          package, and will be removed from the target system.

     There is an extremely rare case where a preserved file bears
     exactly the same modification time as the file installed
     from the release.  If such a file is restored to its origi-
     nal name (as with the -k option), the file would appear to
     be from the release associated with that modification time.
     This could interfere with the use of preserve when future
     releases are installed. Therefore, in these cases, the
     modification time of the file will be increased by one
     second when it is restored, so that it can still be identi-
     fied as a user-modified file when future releases are
     installed.

     It is important to note that when the version appears in the
     pathname of a saved file, it does not mean that the file
     came from version version of the software package, but
     merely that the the file was saved when version version was
     installed.

     Take care to collect and keep copies of the :ver:  files
     saved by preserve, since they can be lost if the same update
     is reinstalled later.

     Currently, preserve depends on the availability of enough
     extra space on the file system(s) receiving the update to
     hold both the files from the update and the preserved files.
     Therefore, it is not recommended that en mass copys of pre-
     vious releases be preserved with preserve, as could be
     caused by touching all of the files named in the bomfiles
     for the package. This should be accomplished by more tradi-
     tional methods of backup.

FILES
     /usr/pkg/bin/preserve




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SEE ALSO
     findmods(1M).





















































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