what is the difference between commands compress, pack and gzip

Thread Tools Search this Thread
Top Forums Shell Programming and Scripting what is the difference between commands compress, pack and gzip
# 1  
Old 09-24-2011
what is the difference between commands compress, pack and gzip

Are the above commands does the same job ?

same functionaliy ?

If so, why do we have three utilities for the same functinality.
# 2  
Old 09-24-2011
Yes in some ways they are the same functionality they intend to compress data.
Some do better than others e.g gzip is better than compress and pack in overall .

compress and gzip are alike in some ways as they are exploit the same algorithm but they differ in some ways.

compress : The compress utility will attempt to reduce the size of the named files by using adaptive Lempel-Ziv coding. Typically, text such as source code or English is reduced by 50-60%. Compression is generally much better than that achieved by Huffman coding (as used in pack ).

pack : The pack command attempts to store the specified files in a compressed form. Wherever possible (and useful), each input file file is replaced by a packed file file.z with the same access modes, access and modified dates, and owner as those of file. If pack is successful, file will be removed.

gzip Is a GNU version of Lempel-Ziv coding (LZ77) which reduces the size of the named files using Lempel-Ziv coding (LZ77). Whenever possible, each file is replaced by one with the extension ‘.gz’, while keeping the same ownership modes, access and modification times.
This User Gave Thanks to h@foorsa.biz For This Post:
Login or Register to Ask a Question

Previous Thread | Next Thread

10 More Discussions You Might Find Interesting

1. UNIX for Beginners Questions & Answers

Compress multiple gzip files

Good afternoon friends. I wanted to make a query, how to compress several files and leave them all in 1, for example flat text files: filename_1.csv filename_2.csv filename_3.csv expected result filename_end.gzip = (filename_1.csv filename_2.csv filename_3.csv) please (2 Replies)
Discussion started by: tricampeon81
2 Replies

2. UNIX for Dummies Questions & Answers

perl pack and unpack commands

I am using pack/unpack to encyrpt a file. syntax is below #!/bin/sh encrypt=`perl -e 'print unpack "H*","yourpassword"'` - echo $encrypt >/file/to/store/encrypted/password pass=`cat /file/to/store/encrypted/password` decrypt=`perl -e 'print pack "H*",$pass'` ... (2 Replies)
Discussion started by: erinlomo
2 Replies

3. UNIX for Advanced & Expert Users

limitation of gzip and compress

Hi, in AIX 6.1 what is the limite of gzip and compress ? I mean what can be at most the size of the file to compress ? Thank you. (1 Reply)
Discussion started by: big123456
1 Replies

4. UNIX for Dummies Questions & Answers

gzip instead of compress

Duplicate threads merged jmc Hi, I have a script wherein I want to use gzip instead of compress. # cat dly_appsfiles_bkp.ksh # # dly_appsfiles_bkp.ksh # date_stamp=`date +%m%d%y` base_dir=/u05/gld1 sub_dir=apps bkp_dir=/u00/backup/GLD1/APPS... (5 Replies)
Discussion started by: narayanv
5 Replies

5. UNIX for Dummies Questions & Answers

perl pack and unpack commands

I have a file that contains user id and corresponding password. Lets say password is "help". The below command will create a hex value for string "help". perl -e 'print unpack "H*","help"' So now password is in encoded format. Then I decoded it in the script where am fetching the... (1 Reply)
Discussion started by: max_payne1234
1 Replies

6. UNIX for Dummies Questions & Answers

difference between 'compress' and 'gzip'

hi can i know the diff between these 2 commands in terms of data compressed (3 Replies)
Discussion started by: anandapani
3 Replies

7. UNIX for Dummies Questions & Answers

SSH Compress Commands

I am brand new to unix and am hoping someone can start me in the right direction. I hope I have the right forum but if not can a moderator move this thread to the right area. I am moving servers and need to back up a folder and its sub folders into a .tar.gz file then want to upload that file... (2 Replies)
Discussion started by: kushti
2 Replies

8. SCO

compress & cpio commands

Our End of Day backup routine uses following script. start End-of-day compress $BASE TO /home/compdir write /home/compdir to DATTAPE end where $BASE=/home2/Rev83 DATATAPE=/dev/rmt/ctape1 write=cpio (not sure about parameters) since I'm new to UNIX, i dont know how to restore data... (1 Reply)
Discussion started by: tayyabq8
1 Replies

9. UNIX for Dummies Questions & Answers

compress and descompress file whit pack

hi i dont can traspassing file from unix sco compress whit pack or compress i dont can descompress whit other program... how i can do descompress that file in windows me.??? thank very much... pd:sorry my inglish (6 Replies)
Discussion started by: jtapia
6 Replies

10. UNIX for Dummies Questions & Answers

compress --> gzip

I have hundreds of ".Z" files that I need to uncompress and gzip. I'm not sure how to handle this in a 'for loop'. I can get the uncompress part, but I'm not sure how to strip the .Z off the filename for the gzip step. Is it possible to pipe the output of uncompress to gzip? (2 Replies)
Discussion started by: 98_1LE
2 Replies
Login or Register to Ask a Question