Archive Utilities

1
Archive Utilities

• Learning Objectives
• To introduce different archive utilities for file
  compression with their usage
• To compare summarized different archive
  utilities

2
Archive Utilities

• Table of Content
• Compress
• gzip compression
• Zip compression (PC Compatible)
• Zip (PC pkzip Compatible)
• Unzip (PC pkunzip Compatible)
• tar archive
• No compression
• Selective restore
• With Compression
• Cpio ( selected reference )
• Summary

3
Summary
Archive Restore List Usage Notes
compress uncompress Compress single file
() gzip gzip -d gzip -l Backward compatible with compress Compress (better ratio) single file
() zip (-r) unzip unzip -v DOS pkzip / Winzip compatible Compress/backup multiple files/ dir.
tar cvf tar xvf tar cvf Backup multiple files/ dir. (cf. gtar ())
cpio -ocvB cpio -icvdB cpio -icvtB Backup Multiple files/ dir. (with owners / group) For your reference only
() Not available in all systems, may need to
download, see www.gnu.org
4
Compress / Uncompress

• Compression single file and available on most
  systems
• Compressed .z file smaller, file date preserved
• Actually compression ratio depend on data (text
  file and database files usually larger)
• ls -l buyer
• 22651778 Nov 16 1845 buyer.dbf
• compress buyer.dbf
• ls -l buyer
• 3603257 Nov 16 1845 buyer.dbf.Z
• uncompress buyer.dbf.Z
• ls -l buyer
• 22651778 Nov 16 1845 buyer.dbf

5
gzip Compression

• Backward compatible with compress, better
  compression ratio
• Available from GNU www.gnu.org
• gunzip un-compresses
• gzip h
• gzip 0.7 (5 Jan 93)
• usage gzip -cdfhLrtvV19 file ...
• -c --stdout write on standard output, keep
  original files unchanged
• -d --decompress decompress
• -f --force force overwrite of output file
  and compress links
• -h --help give this help
• -L --license display software license
• -r --recurse recurse through directories
• -t --test test compressed file integrity
• -v --verbose verbose mode
• -V --version display version number
• -1 --fast compress faster
• -9 --best compress better
• file... files to (de)compress. If none
  given, use standard input.

6
tar archive
tar cvf /tmp/tar2.tar a letter0 1K a secret/
0K a secret/letter1 1K a secret/letter2 1K

• Traditional archive utility backup directory
  tree(s)
• tar cvf /tmp/tar1.tar .
• a ./ 0K
• a ./letter0 1K
• a ./secret/ 0K
• a ./secret/letter1 1K
• a ./secret/letter2 1K
• tar xvf /tmp/tar1.tar
• Restores the directory tree

7
Disks Usage Statistics

• df display free blocks and of files in each
  file system
• df head
• /proc (/proc ) 0 blocks
  934 files
• / (/dev/dsk/c0t3d0s0 ) 226544 blocks
  280996 files
• /dev/fd fd ) 0 blocks
  0 files
• /var (/dev/dsk/c0t3d0s3 ) 1480320 blocks
  252851 files
• /cache (/dev/dsk/c0t3d0s4 ) 308472 blocks
  243243 files
• /home (/dev/dsk/c0t3d0s7 ) 1408858 blocks
  284098 files
• /tmp (swap ) 2903968 blocks
  10169 files
• /var/mail(mail/mail )14054672 blocks
  1097254 files
• /var/spool/uucp (mail/var/spool/uucp) 3450734
  blocks 350809 files
• du display disk usage statistics (in number of
  512k blocks)
• du head -5
• 282 ./zmodem
• 14 ./gzip-0.7/msdos
• 2 ./gzip-0.7/os2
• 662 ./gzip-0.7
• 3626 ./mail

du shows disk usage of directories in 512k blocks
8
User Groups (2)

• View users of a group
• ypcat group grep comp111
• comp11140000kwchiu,john
• usage groupmod -g gid -o -n name group
• Renaming a group (super-user only)
• groupmod
• usage groupmod -g gid -o -n name group
• groupmod -n cs111 comp111
• Deleting a group
• groupdel
• usage groupdel group
• groupdel cs111