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Analog 5.22: Aliases

After analog has read each logfile entry, it then applies aliases to each of the items. First, if you have a case insensitive filesystem, analog converts the filename to lower case. Usually analog assumes that Unix and BeOS filesystems are case sensitive and other systems are case insensitive. You might want to override its choice, if, for example, you have transferred files from one machine to another, so as to use the convention on the original machine. You can do this by the commands 
CASE INSENSITIVE
CASE SENSITIVE
There are similar commands for usernames, if your logfile records these. By default, usernames are always case insensitive, but you can specify 
USERCASE SENSITIVE
to override this.
Next it applies built-in aliases to each item. For example, it knows that %7E in a filename or referrer is equivalent to ~ and translates it accordingly. It also strips off the directory suffix from any filenames which have it. This suffix is normally index.html, but you can specify another one instead with a command such as 
DIRSUFFIX default.htm
(You can only have one DIRSUFFIX.) There are other built-in aliases for other items: for example, hostnames are converted to lower case at this point.
After this, it applies user-specified aliases to each item. These aliases are useful if, for example, you know that two filenames correspond to the same file, or if you want to translate local hostnames to their internet equivalents. You specify aliases by commands like 
FILEALIAS /football.html /soccer.html
HOSTALIAS lion lion.statslab.cam.ac.uk
There is also the special command FILEALIAS none, which cancels any other file aliases which might have been specified.

The alias commands for the other items are called BROWALIAS, REFALIAS, USERALIAS and VHOSTALIAS. Only one alias is ever applied to any item. So after 

FILEALIAS /football.html /soccer.html
FILEALIAS /soccer.html /brazil.html
the file /soccer.html would get translated to /brazil.html, but /football.html would only get translated to /soccer.html and would not see the second alias.

You can also use wildcards in ALIAS commands: ? matches any one character and * matches any number of characters (including none). And on the right-hand side, you can use $1, $2 etc. to represent the parts of the original name matched by the *'s. As a special abbreviation, if there is exactly one * on the left-hand side, then a * on the right-hand side can be used to represent $1. So, for example, 

FILEALIAS /*/football/* /soccer/
would translate /sport/football/rules.html to just /soccer/, but either of 
FILEALIAS /*/football/* /$1/soccer/$2         # or
FILEALIAS /sport/football/* /sport/soccer/*
would translate /sport/football/rules.html to /sport/soccer/rules.html.

You can use $$ to get an actual $ on the right-hand side. Or you can prefix the right-hand side with "PLAIN:" to treat any $'s and *'s on the right-hand side literally. For example 

FILEALIAS /*/football/* PLAIN:/$1/soccer/$2
would translate /sport/football/rules.html to exactly /$1/soccer/$2

Analog's *'s are un-greedy: if there are two possible ways of matching, the part of the expression on the left matches as little as possible. This is more often what you want. But it contrasts with Perl's regular expressions, for example. (Oh, two consecutive *'s are completely useless, but if you try it they are collapsed into one before counting the $1, $2, etc.)

The behaviour of FILEALIAS and REFALIAS can be slightly unintuitive if the file has search arguments.

A warning to Unix users: if you put an ALIAS command on the command line with +C, the shell may try and expand $1 etc., which is not what you want. To stop the shell doing this, put the command in single quotes instead of double quotes.

There is another set of alias commands, called output aliases. They don't alias items, but individual lines from particular reports (and they never combine lines, even if two lines end up with the same name). For example, the command 
TYPEALIAS .txt ".txt (Plain text files)"
would provide an explanation of thoteing (German), Dimitris Xenakis (Greek), Laszlo Nemeth & Andras Kemeny (Hungarian), Gustaf Gustafsson & Valberg Larusson (Icelandic), Furio Ercolessi, Luca Andreucci, Alessio Bragadini & Marco Bernardini (Italian), Takayuki Matsuki, Stephen Obenski, Motonobu Takahashi, Kaori Chikenji & Kazuto Ishigaki (Japanese), Byungkwan Kim & InChang Oh (Korean), Jurijs Turjanskis & Anda Bimbere (Latvian), Ingrid (Lithuanian), Jan-Aage Bruvoll, Espen Bjarnø & Pål Løberg (Norwegian Bokmål), Magni Onsøien & Trond Øksendal (Norwegian Nynorsk), Wlodek Lapot, Tomek Wozniak & Marcin Sochacki (Polish), Ivan Martinez, Paulino Michelazzo & Ronan Lucio Pereira (Brazilian Portuguese), Jaime Carvalho e Silva (European Portuguese), Alex Mihaila (Romanian), San Sanych Timofeev, Boris Litvinenko & Vyacheslav Nikitich (Russian), Mile Peric (Serbian), Stefan Billik (Slovak), Andrej Zizmond & Dalibor Cvijetinoviè (Slovene), Javier Solis, Alexander Velasquez, Alfredo Sola, Martin Perez, Nelson Tactuk, Javier Kohan & J. L. García (Spanish), Björn Malmberg, Frank Osterberg, Wesley Schaal & Christian Rose (Swedish), Nezih Erkman & Dikran Diragormacioglu (Turkish), and Yaroslav Boychuk (Ukrainian).

Finally, thanks to all of you for using the program!

Go to the analog home page.

Stephen Turner
20 March 2002

Need help with analog? Use the analog-help mailing list.

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Analog 5.22: Aliases

After analog has read each logfile entry, it then applies aliases to each of the items. First, if you have a case insensitive filesystem, analog converts the filename to lower case. Usually analog assumes that Unix and BeOS filesystems are case sensitive and other systems are case insensitive. You might want to override its choice, if, for example, you have transferred files from one machine to another, so as to use the convention on the original machine. You can do this by the commands 
CASE INSENSITIVE
CASE SENSITIVE
There are similar commands for usernames, if your logfile records these. By default, usernames are always case insensitive, but you can specify 
USERCASE SENSITIVE
to override this.
Next it applies built-in aliases to each item. For example, it knows that %7E in a filename or referrer is equivalent to ~ and translates it accordingly. It also strips off the directory suffix from any filenames which have it. This suffix is normally index.html, but you can specify another one instead with a command such as 
DIRSUFFIX default.htm
(You can only have one DIRSUFFIX.) There are other built-in aliases for other items: for example, hostnames are converted to lower case at this point.
After this, it applies user-specified aliases to each item. These aliases are useful if, for example, you know that two filenames correspond to the same file, or if you want to translate local hostnames to their internet equivalents. You specify aliases by commands like 
FILEALIAS /football.html /soccer.h