Scenario - a contact emails you a [tjw]ar file containing - let's say - 20 files within it. You unpack it in a directory that already has 15 files in it ... and you end up with 30 file. Hmm - not what you might have expected; you were expecting 35 files in total.
What went wrong? Five of the files that you unpacked had names that were named
the same as files that already existing in the directory in which you unpacked and by unpacking there you have
overwritten the original files. Which could be a major issue if the files had the same name in the existing directory and archive, but the content differed.
It's to avoid problems like this that you need a
best practise for creating and unpacking tar / jar / war files
Best Practise:
1. If you receive a jar / war / tar file, you should create an empty directory and unpack it within that. Yes - that might (should) result in a directory that contains only another directory ... but that's
far better than the potential corruption if you unpack into a populated area.
2. If you are creating a jar / tar file, you should move to the directory level ABOVE the one in which the files are contained, and pack the file from there:
tar czf htdocs_8.2.2.tgz htdocs_8.2.2
and you should ideally name the file and the directory with a version number or date.
Regrettably, if you're creating a war file (web archive), you'll need to flout good practise #2 and pack it from within the directory:
jar cf /tmp/marmite.war *
as .war files need to be created in this was to be able to be unpacked and (auto)deployed without changing paths or renaming.
Advise from our Deploying Apache httpd and Tomcat course which I've been running in the latter half of this week. (written 2012-07-26, updated 2012-08-11)
Associated topics are indexed as below, or enter http://melksh.am/nnnn for individual articles
A652 - Web Application Deployment - Tomcat -Sourcing, Installing and Initial Testing [837] Tomcat - Shutdown port - (2006-08-18)
[1049] Java 6, Apache Tomcat 6. - (2007-01-21)
[1550] Java (JSP and Servlet examples) live on our server - (2008-02-23)
[2088] Changing the 404 - file not found - page in Tomcat - (2009-03-18)
A502 - Web Application Deployment - Java - Basic Tools [754] tar, jar, war, ear, sar files - (2006-06-10)
[1082] Straight from the .jar - (2007-02-16)
[1192] What are WEB-INF and META-INF directories? - (2007-05-18)
[1562] Java Compiler - needs all classes, compiles them all too - (2008-03-03)
[1771] More HowTo diagrams - MySQL, Tomcat and Java - (2008-08-24)
[1909] javax.servlet cannot be resolved - how to solve - (2008-11-26)
[2153] Class Loading and Variable Conversion in Java - (2009-05-02)
[2422] Looking inside Java classes - javap and javadoc - (2009-09-25)
[2859] Using java, javac, jar, and CLASSPATH - a simple example - (2010-07-07)
[3151] Disassembling Python and Java - previously compiled code - (2011-01-29)
[4412] Java -making sure you have the right versions - (2015-02-02)
A101 - Web Application Deployment - Linux -An Introduction For Users [73] vi - full circle - (2004-10-04)
[74] pushd and popd - (2004-10-05)
[152] Aladdin, or careful what you wish. - (2004-12-15)
[249] An easy way out - (2005-03-17)
[430] Linux commands - some basics - (2005-08-31)
[431] File permissions of Linux and Unix systems - (2005-08-31)
[593] Finding where the disc space has gone - (2006-02-06)
[659] Web Application Components - (2006-03-28)
[679] More or less on the edge of the page - (2006-04-11)
[703] Copying files and preserving ownership - (2006-04-28)
[710] Linux training Glasgow, Python programming course Dundee - (2006-05-05)
[711] THE home directory or MY home directory - (2006-05-06)
[749] Cottage industry or production line data handling methods - (2006-06-07)
[984] Cardinal numbers and magic numbers - (2006-12-14)
[1012] Moving files between Windows / DOS and Linux / Unix - (2006-12-30)
[1013] Copy multiple files - confusing error message from cp - (2006-12-30)
[1068] ls -l report, Linux / Unix - types and permssions - (2007-02-06)
[1259] Where am I and how did I get here? - (2007-07-05)
[1287] Work and play at Well House Manor - Football and Shell Shortcuts - (2007-08-02)
[1288] Linux run states, shell special commands, and directory structures - (2007-08-03)
[1366] awk - a powerful data extraction and manipulation tool - (2007-09-25)
[1408] Wireless hotel tips - FTP and Skype connections failing - (2007-10-26)
[1438] Copy and paste / cut and paste and other vi techniques - (2007-11-20)
[1527] Selecting file names in a shell - one word or another - (2008-02-02)
[1651] ls command - favourite options - (2008-05-23)
[1764] Yank and Push - copy and move in vi - (2008-08-21)
[1803] FTP passive mode - a sometimes cure for upload hangs - (2008-09-20)
[1893] Some Linux and Unix tips - (2008-11-18)
[1897] Keeping on an even keel - (2008-11-21)
[1902] sstrwxrwxrwx - Unix and Linux file permissions - (2008-11-23)
[1904] Ruby, Perl, Linux, MySQL - some training notes - (2008-11-23)
[2201] Running straight from the jar, but not from a tar - (2009-05-26)
[2203] Always use su with minus. And where do programs come from? - (2009-05-27)
[2299] How much space does my directory take - Linux - (2009-07-20)
[2300] What does x on a linux directory mean? - (2009-07-21)
[2479] Accidentally typed ci rather than vi? - (2009-10-27)
[2494] Making Linux Politically correct - (2009-11-06)
[2636] Linux - useful tips including history and file name completion - (2010-02-15)
[2831] Recording (a macro) in vi - (2010-06-27)
[3179] Oops - I typed ci not vi, and have lost my file ... - (2011-02-21)
[3256] Displaying a directory or file system tree - Linux - (2011-04-22)
[3791] The Kernel, Shells and Daemons. Greek Gods in computing - (2012-07-01)
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Know Python or PHP? Want to learn Perl too?Town Clean - MelkshamWell House Manor at Dawn ... and later in the dayPHP sessions - a best practice teaching examplePacking a tar, jar or war file - best practiseMaking things happen - litter and ASB and lost dogs in MelkshamFpdf - generating .pdf documents easily from your PHP programWant to escape the Olympics? Learn to program in the countryside!The Melksham News - July 2012 - Part 2, TransWilts Rail, Wilts and Berks CanalReturning guests - a sign of a good product. Cream teas and hotel rooms.