backup - backup files

     backup [-djmnorstvz] dir1 dir2


     -d   At top level, only directories are backed up

     -j   Do not copy junk:  *.Z, *.bak, a.out, core, etc

     -m   If device full, prompt for new diskette

     -n   Do not backup top-level directories

     -o   Do not copy *.o files

     -r   Restore files

     -s   Do not copy *.s files

     -t   Preserve creation times

     -v   Verbose; list files being backed up

     -z   Compress the files on the backup medium


     backup -mz . /f0    # Backup current directory compressed

     backup /bin /usr/bin
                         # Backup bin from RAM disk to hard disk


     Backup (recursively) backs up the contents of a given directory  and  its
     subdirectories  to  another  part of the file system.  It has two typical
     uses.  First, some portion of the file system can be backed up onto 1  or
     more diskettes.  When a diskette fills up, the user is prompted for a new
     one.  The backups are in the form of mountable file systems.   Second,  a
     directory  on  RAM  disk  can be backed up onto hard disk.  If the target
     directory  is  empty,  the  entire  source  directory  is  copied  there,
     optionally  compressed  to save space.  If the target directory is an old
     backup, only those files in the target  directory  that  are  older  than
     similar  names  in  the source directory are replaced.  Backup uses times
     for this purpose, like make.  Calling Backup as Restore is equivalent  to
     using  the  -r  option; this replaces newer files in the target directory
     with older  files  from  the  source  directory,  uncompressing  them  if
     necessary.  The target directory  contents  are  thus  returned  to  some
     previous state.