Exercises, examples and other material relating to training module A101. This topic is presented on public courses
If you're going to be deploying web applications on a server that's running Linux (or Solaris, AIX, HPUX, OSX or another flavour of Unix) you'll need to know a little background about the operating system. This module teaches you the foundations of working with a Linux system, concentrating on things you'll need to know if you're going to be deploying Web applications there.
Articles and tips on this subject | updated |
593 | Finding where the disc space has gone Murphy's fourth law states that data expands to fill the disc space available, and there's a collaboration that states that it reaches that full point when you're trying to save a file you should have saved a long time ago during a complex operation.
I'm not a good one at deleting old backup files; ... | 2012-11-04 |
3819 | Packing a tar, jar or war file - best practise 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 ... | 2012-08-11 |
3791 | The Kernel, Shells and Daemons. Greek Gods in computing The Greek Gods didn't like washing up or ironing. So they employed mortals to to it. Problem was that those mortals didn't last for ever, and sometimes went on strike over one thing and another. So The Gods did a deal with some of the current batch of mortals, and it went like this: "We will make you ... | 2012-07-14 |
3256 | Displaying a directory or file system tree - Linux How can you display your whole file tree on a Linux system? With the tree command!
|-- abo
|-- access_log
|-- adarrivals.txt
|-- adhoc_private
| |-- adhoc.conf
| |-- businesslogic.inc
| |-- page_layout.htp
| |-- sampledata.sql
| |-- sqlwrapper.inc
| `-- webhelpers.inc
|-- backups
| |-- emma
| |-- net.cgi.tgz
| |-- net.html.tgz
| |-- net.other.tgz
| |-- nettouk.sql
| |-- nettouk.sql.gz
| `-- nfr
| |-- accesslog_nfr.co.uk_4_24_2010
| |-- perly
| `-- snapshot
|-- batch
| |-- ilog.php
| |-- perl_web_anal
| `-- php_web_anal
|-- booksonly.sql
• ... | 2011-04-22 |
3179 | Oops - I typed ci not vi, and have lost my file ... Sitting writing late at night, I occasionally misspoll something; no great problem - I can go back and correct it, or if I fail to do so occasionally my kind reader will work out whaT I mean and forgive. But occasionally, when I'm typing in commands at the command line, one character can cause a big ... | 2011-02-24 |
2831 | Recording (a macro) in vi There are time that I'm editing a file with vi, and I note that my editor says "recording on the bottom of the screen / status bar.
What have I done? Is this useful? Can / should I turn it off?
• If you type "q" followed by another keystroke in command mode, you start recording into a macro buffer ... | 2010-06-27 |
2636 | Linux - useful tips including history and file name completion Linux is feature rich - it's so feature rich that it's daunting to know where to start when teaching about it - what features to include and what to leave out.
It's twenty to nine at night, and I'm still hear in "The Wilts" training room, just getting down to "the Mouth" which I would have expected ... | 2010-03-03 |
2494 | Making Linux Politically correct [trainee@easterton ~]$ man ls
Manual page displayed here
[trainee@easterton ~]$ woman ls
-bash: woman: command not found
[trainee@easterton ~]$ alias woman=man
[trainee@easterton ~]$ woman ls
Manual page displayed here
[trainee@easterton ~]$
OK - I'll admit that this is quite a trivial use of the "alias" ... | 2009-11-07 |
2479 | Accidentally typed ci rather than vi? You're using the Linux command line interface, you get distracted, and you type in ci. Oops - before you know it, you've lost your file ... at least it has disappeared from where you expected it to be:
[root@holt conf]# ci server.xml
server.xml,v >
initial revision: 1.1
done
[root@holt conf]#
What's ... | 2009-10-30 |
2300 | What does x on a linux directory mean? Trick question (I don't ask too many, I hope ... and those that I do ask are designed to be thought provoking):
What does the x bit in permission strings mean?
Most delegates who've done a bit of Unix or Linux before will tell me it's the exexcutable bit - says whether a file can be run as a program ... | 2009-07-23 |
2299 | How much space does my directory take - Linux The index card in the library for "War and Peace" takes a lot less space that the book itself, and so it is when you ask Linux or Unix "how much space is taken in this directory" ... you'll be told how big each of the files are, and how big the index table for each subrirectory is. Here's an example ... | 2009-07-22 |
2203 | Always use su with minus. And where do programs come from? When you're using the su command to do systems admin work as route, you should always add the - options (minus sign on its own) to start a new root environment too. This means that the PATH that executable files are found from is replaced (amongst other things) - so you can find things like ifconfig ... | 2009-05-27 |
2201 | Running straight from the jar, but not from a tar Why can you run applications in Java straight from the jar, but you'll never find mainstream applications extracting their code from a tar file? It all comes down to the different indexing structure.
A tar file was originally designed as a "tape archive". So it's a sequential file that contains file ... | 2009-05-26 |
1288 | Linux run states, shell special commands, and directory structures Some useful notes from the board ...
Run states of Unix and Linux systems:
0 - Halted
1 - Single User
2 - Multiuser
3 - Full Multiuser (inc servers)
5 - Same + X Windows
6 - transient reboot
Install Order for LAMP
Linux ...
... then Apache httpd
... then MySQL
... then PHP.
PHP must be after MySQL ... | 2009-01-22 |
1897 | Keeping on an even keel Some (but not all) Open Source products have a numbering system where the second number is even for a production release and odd for a development release - so if you're looking to install one of these products on a live machine for customer use, you should make sure you stick with the even release even ... | 2008-11-24 |
1902 | sstrwxrwxrwx - Unix and Linux file permissions Have you ever wondered about those letters that turn up on the left of a long listing (ls -l) report? Here's an example:
drwxrwxrwt 8 root wheel 272 17 Nov 2007 Shared
drwxr-xr-x 14 chris ellis 476 29 Sep 2007 chrise
drwxr-xr-x 270 graham ellis 9180 23 Nov 07:25 grahame
drwxr-xr-x 34 lisa ellis 1156 27 Sep 06:44 lisae
drwxr-xr-x 29 trainee trainee 986 5 Sep 03:55 trainee
-rw-rw-r-- 1 graham ellis 294 23 Nov 07:41 uu
-rw-r----- 1 graham ellis 922 21 Nov 08:45 wb
-rw------- 1 graham ellis 5143 23 Nov 07:25 xx
They're ... | 2008-11-24 |
1904 | Ruby, Perl, Linux, MySQL - some training notes We have just come to the end of a solid 12 days of training ... and we are just getting ready for the next week, with delegates arriving this evening. There's a lot going on behind the scenes, even over this weekend, with the hotel to be prepared as well as the training course. (Picture - our clean ... | 2008-11-24 (longest) |
1893 | Some Linux and Unix tips How to make a woman equal to a man
[trainee@easterton ~]$ man ls
[trainee@easterton ~]$ woman ls
-bash: woman: command not found
[trainee@easterton ~]$ alias woman=man
[trainee@easterton ~]$ woman ls
[trainee@easterton ~]$
In Linux and Unix, the man command gives you a manual page ... but there is ... | 2008-11-18 |
1803 | FTP passive mode - a sometimes cure for upload hangs Are you on the road (as I am today) and having trouble FTPing files up to your server (as I was today)? Symptom - the connection sets up just fine, it's great when you're looking for files, but as soon as you put an upload / download instruction in, it hangs ...
I've switched passive mode off ... that's
passive ... | 2008-09-22 |
1764 | Yank and Push - copy and move in vi If you want to copy a number of lines, Yank them into your paste buffer, move the cursor to where you want the copy, and Push the duplicate copy.
Example ....
10Y (yank 10 lines - the current followed by the next 9)
move cursor
P (push those lines into their new position)
Alternatives / variants ... | 2008-08-21 |
1651 | ls command - favourite options The ls command has so many options that it's confusing. Here are my personal favourite selection:
How to display the information
A long listing with ownerships, sizes, dates and permissions - ls -l
Names, with * / and @ to indicate executable, directory and link - ls -F
Which information to display
Information ... | 2008-05-23 |
1527 | Selecting file names in a shell - one word or another If you want to select all file names that include the words "cat" or "dog" in them with file name matching, you can do so using curly braces - that's supported by most modern shells as part of what is known as "globbing".
Here's an example - I've just been copying images off my digital camera and I ... | 2008-02-02 |
1408 | Wireless hotel tips - FTP and Skype connections failing I'm on line this week through a Spectrum interactive account, who's web site tells me that they have won a contract to supply BAA at Heathrow Terminal 5 and that they have an exclusive 7 year deal at Travelodge, where I have been staying. It's not all been a bed of roses - quite apart from a major loss ... | 2007-11-20 |
1438 | Copy and paste / cut and paste and other vi techniques * If you want to duplicate a line, you can yank it with Y into the default yank buffer, then move your cursor and push it out with p or P to push it after or before the current line.
* To move a line, delete it with dd which puts it into the yank buffer, then push it with p or P.
* The number of lines ... | 2007-11-20 |
1366 | awk - a powerful data extraction and manipulation tool Unix and Linux come with a whole toolkit of utility programs for filtering, sorting and manipulating data. As a "one off" job, you can use them from the command line, and for repeated jobs you can save a series of instructions for these tools in a shell script. Yesterday, I ran a private shell scripting ... | 2007-09-25 |
1287 | Work and play at Well House Manor - Football and Shell Shortcuts We're running a Linux and LAMP course this week - great group and I'm going to be sorry when it's the end of the course.
Yesterday we had a cold buffet lunch for a change, and made the best of the lovely weather and spacious garden to relax for a while - we do a long day, and so a good break at lunch ... | 2007-08-01 |
1259 | Where am I and how did I get here? When you as "which directory am I in" with the pwd command, are you told the real directory you are in, or the one you cd'd into? You are normally tod the one you've cd'd to.
What's the difference? you may ask The difference is that you might want to find out where you really are on the file system ... | 2007-07-05 |
1068 | ls -l report, Linux / Unix - types and permssions What does drwtrwx--- mean on the start of your ls-l report?
The first character (d in my example) tells you the type of symbol you have on the file system, as follows:
d - a directory;
b - a block-type special file;
c - a character-type special file;
p - a named pipe;
l - a symbolic link;
S - a socket;
s ... | 2007-02-07 |
1012 | Moving files between Windows / DOS and Linux / Unix Text files written on a Windows or DOS operating system use a carriage return character (ASCII decimal equivalent 13) followed by a line feed (ASCII decimal equivalent 10) as their line terminator, but on Linux, Unix and OS X systems, just the line feed character is used. And sometimes you'll find that ... | 2007-01-02 |
1013 | Copy multiple files - confusing error message from cp Thought you might like me to share this one ...
Copying a whole series of files into a directory (Linux, Unix, OS X) using cp, you give a whole series of source files followed by the name of the target directory. Add the -r option is you want to specify subdirectories to be copied recursively in your ... | 2006-12-30 |
984 | Cardinal numbers and magic numbers A cardinal number, in computing terms, is a term that's sometimes used to refer to a fixed condition - in other words, you might call a function with one parameter should of the usual number, and the final value will be assigned a cardinal number that can't occur there in reality. For example, you might ... | 2006-12-21 |
749 | Cottage industry or production line data handling methods If you're running a cottage industry, for efficiency's sake you'll run the first process on each of your raw components first, and store the partially-completed elements in a basket as they're processed. When you've completed that first process, you'll then apply the second process to each element ... | 2006-06-07 |
73 | vi - full circle I started doing Solaris training in the early 1990s - it seems an age ago (probably because it is an age ago!) and one of the courses we did was an "Introduction to Solaris" course which ran for 2 days and had a quarter day or so on the vi editor. With the takeoff of our Perl and Java courses in the ... | 2006-06-05 |
703 | Copying files and preserving ownership If you're copying a file on a Unix / Linux / OS X operating system, use the cp command. Use cp -r to copy a directory and all its contents - the -r means "recursive". If you use the cp command to copy files that you have read access to, but do not own, then you'll be made the owner of the new copies; ... | 2006-06-05 |
711 | THE home directory or MY home directory When a user logs in to a Linux system, the user is taken to their home directory (folder) - a place where their personal work is kept in files and a further structure of sub-directories as appropriate. Configuration files are also kept in their home directory - files like .my.cnf for their MySQL defaults ... | 2006-05-06 |
710 | Linux training Glasgow, Python programming course Dundee We run training courses so often in Scotland that I don't even need a map anymore, except perhaps a streetmap page showing the roads in the immediate vicinity of the training venue. But how do we reach our potential client base? How do they find out about us?
Firstly, we have good and tailored web ... | 2006-05-05 |
Logging in and user accounts.
Files and directories.
File name matching and specifying multiple files.
Commands for examining file contents.
Manipulating the file system.
Copying, moving and deleting files and directories.
Changing the contents of a file.
vi basics.
Summary of vi commands.
The most basic.
Second level vi commands.
File permissions and some other useful commands.
File permissions.
Metacharacters in Nix commands.
Other useful commands.
Combining commands with shell programming.
Distribution and archive files and file transfers.
Handling tar and gzip files.
Transferring files using FTP.
Logging in to remote machines.
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