If, in response to an event, a program adds entries to a file, usually identifying the event and its source, then the file is called a log file. Possible event sources:

• The result of certain user actions.
• Interrupts coming into the program from the equipment.
• Events generated by the programs themselves (for example, obtained as a result of calculations).
• Events generated by software errors (so-called “exceptions”).
• Events from the operating system or other program, as well as events from any other source.

In a word, we are talking about changing states in a running and running program. The simplest option log file - normal text file with row records. All information in log files is recorded in a specific format, which makes it possible to subsequently understand the reasons for the occurrence of events.

Where are log files used?

The list of uses for log files is huge. Files of this type used wherever it is necessary to trace the history of something software process, keep a record of the status of devices and machines, monitor user actions, incl. and for the purpose of ensuring safety. And in many other cases. To search and analyze data in log files, as a rule, independent software is used, which allows you to quickly and visually study the logged work data software system. Many log files are very large, so you have to either regularly overwrite their outdated contents, or create entire collections of log files with names including, for example, the date. In many cases, they prefer to deal with databases instead of log files.

Useful examples

Let's give a couple of examples of using log files. If a lot of unexpected exceptions occur in the program being debugged, then they can be recorded in a log file for subsequent error analysis. As another example, we can point to logging data about connected users in multi-user client-server systems. This allows you to track unauthorized transactions they perform.

If you, dear reader, actively use the Internet, then you have probably come across the following words and phrases: log, log file or logs server. And have you ever wondered what it is? In this article today we will try to answer this question in detail.

Log(or, in other words, logs server, log file, these phrases are synonyms) is a text format file in which all data about all actions of any users on the servers are recorded, be it local servers any organization or web server of a certain host provider on which sites operate, or the FTP server of your local network.

Entered into log files detailed information about which user accessed the server resources, his IP address, his MAC address network card, from which resource and for what key queries the login was made, which pages on the server were visited by him and how long he spent viewing them. In addition, the log file records which files were downloaded from the server or uploaded to it. As we can see, log files are simply a storehouse of information about all visitors and server users.

Let's talk about web server log files, because they are most often viewed by almost every first-time system administrator.

Every time any user accesses the website, it is recorded in a log file. In this case, several events are triggered.

1. Making a page request. When the user enters address bar your browser the name of an Internet resource and presses the Enter key, the browser searches for the required server in accordance with certain rules and sends it a request to display the page. The request sends the following information to the server:

• IP address of the computer from which the request to receive the page was sent (or IP address of the proxy server used by the client);
• address of the requested Internet page (IP address);
• date and time the request was sent to the server;
• information about the geographic location of the client who made the request to the server (or the location of the proxy server used by the client);
• the name and version of the Internet browser used by the client, from which the request to the server was made;
• the address of the web page from which the transition was made.

2. Transfer of the requested page to the client’s browser. During this event, the server transmits the requested data (which can be presented in the form of a web page, file, cookie, etc.) to the client’s computer, more precisely, to the browser with which the previous event was triggered.

3. Recording to a log file. In this case, the server records all received information in a log file, which is also called an event log.

The data in the log file is quite incomprehensible information for an unprepared beginner, but for system administrators this is a completely understandable and meaningful text that can serve as the basis for taking any action or even criminal prosecution of the client (of course, if access to the resource was illegal, for example, a hacker hack, which resulted in the removal of the database stored there from the server with data bank cards company's clients).

But when analyzing the event log files ( log-files) system and network administrators It should be taken into account that the data obtained are still not 100% real; the deviation in them is usually 5-10% due to various technical and technological features of the equipment used and its settings. However, if the load on the site is more or less constant (in other words, the administration does not conduct any active advertising campaigns to attract visitors, as a result of which site traffic increases by orders of magnitude), then the error values ​​obtained during transmission can be considered more or less constant and become it is possible to compare statistics for past periods.

Of course, you can read and analyze it yourself logs, but this is quite inconvenient and very labor-intensive. To obtain summary reports and statistics on log files, special software called “Log File Analyzers” is used. The most popular and well-known are the following software products: Analog, Webalizer, Webtrends, NetPromoter, WebAnalizer, Loganalyzer.

In this article, we will not dwell in great detail on the functionality of these programs; we will only say that they are all very convenient tools for analyzing a log file and displaying very detailed and clearly presented information required by the system administrator.

As we can see, logs are a very powerful tool for analyzing the activities of visitors on the server.

We hope that the information provided in this article was at least somewhat useful to you.

Concept

Server logs (log files, server log)- files stored on the server that contain system information of the server, as well as logging all possible data about the visitor of the web resource.

Logs are used by system administrators to analyze visitors, studying the patterns of behavior of certain groups of users, as well as obtaining various information about them, such as: the browser used, IP address, data on the client’s geographic location and much more. In addition to analysis, in this way you can find out about unauthorized access to the site, find out more precisely who exactly made it, and transfer data about this case to the appropriate authorities.

The data in the log file, in its pure form, will not be understandable to ordinary users, who will see in all this just a set of characters in an incomprehensible order. But for system administrators and web developers, this is quite readable text, and quite useful information.

Sequence of events

Every time a client accesses a web resource, several events are triggered at once, the sequence of which we will talk about.

1. Making a page request. When entering an address into the browser line, or when following an active web link, for example, from a page search results, the browser searches for and connects to the server on which the page is located and makes a request for it. At the same time, it transmits the following information to the server:
- IP address of the client computer that requests the page (if using a proxy server, the IP address of your proxy);
- address of the Internet page requested by the user (IP address);
- exact time and the date on which the request was made;
- data about the actual location of the client (if a proxy server is used, then the actual proxy address);
- information about the browser used by the client (name, version, etc.);
- data about the web page from which the client transferred.

2. Transfer of the requested data. The requested data (web page, files, cookies, etc.) is transferred from the server to the user’s computer.

3. Write to the server log. After everything, a log entry occurs, which indicates all the data that appeared in the past two events. This is all the information sent in the first paragraph, as well as information about the transmitted data.

How to view server logs

Log files are stored in a file access.log no matter what type of web server you use (Apache, Nginx, squid proxy, etc.) This file is a text document, on each line of which one appeal is written. Recording formats in access.log quite a lot, but the most popular is combined, in which the entry has the following form and sequence:

Code: %h %l %u %t \"%r\" %>s %b \"%(Referer)i\" \"%(User-Agent)i\"
Where:

%h- host/IP address from which the request was made;
%t- time of the request to the server and server time zone;
%r- version, content and type of request;
%s- HTTP status code;
%b- the number of bytes sent by the server;
%(Referer)- URL source of the request;
%(User-Agent)- HTTP header, with information about the request (client application, language, etc.);
%(Host)- the name of the Virtual Host that is being accessed.

in finished form given line looks something like this:

127.0.0.1 - - "GET /index.php HTTP/1..0 (compatible; MSIE 7.0; Windows NT 5.1)"

Reading logs manually will take quite a lot of time and effort. Therefore, experienced webmasters use special software called “Log File Analyzers”. They analyze all the data, which is quite difficult for humans to read, and produce structured data. These are programs such as: Analog, WebAnalizer, Webalizer, Awstats, Webtrends, etc. Types of special software quite a lot, among them there are both paid programs and free ones. Therefore, I am sure that everyone will find something to their liking.

Where to find site logs

If you have regular hosting, then most likely you will have to write to your hoster and request logs from him. Also, quite often, you can request them through the hosting panel. Different hosters do it differently. For example, to request from my hoster, just click on home page panels:

If you have access to system folders server, then you can find the logs at /etc/httpd/logs/access_log in 99 cases out of 100.

Error log error.log

Error.log- a file in which logs are also kept. But not visitors, but errors that occurred on the server. As is the case with access.log, each line of the file is responsible for one error that occurred. The recording is carried out taking into account such information as: the exact date and time of the error occurrence, the IP address to which the error was issued, the type of error, as well as the reason for its occurrence.

Conclusion

Logs are quite a powerful and informative tool to work with. But nowadays, they are replaced by tools such as Yandex.Metrica, Google Analytics, etc., thereby making our lives easier. However, if you plan to develop, grow and learn something new, I certainly recommend that you get to know this topic better.

You"re here because you have a file that has a file extension ending in .log. Files with the file extension .log can only be launched by certain applications. It"s possible that .log files are data files rather than documents or media , which means they"re not meant to be viewed at all.

what is a .log file?

The LOG file extension is used for a Log File that is utilized by multiple programs and operating systems. It acts as records that are kept by computer programs for every activity undertaken. Recording events of a computer’s activity is relevant to its day to day processing. It provides a way for the system to be diagnosed in cases where there might be problems encountered that need immediate solutions. This is evident with large and complex systems where events and activities are essential in understanding the applications involved. All of these events are saved in a LOG file together with names of installed files and lists of their location. There are also other software frameworks and operating systems that execute sophisticated ways of using LOG file. “Syslog” is computer logging that separates software messages from software that analyzes and reports it. It is also used for analysis, debugging messages, generalized information and management of the computer system.

how to open a .log file?

Launch a .log file, or any other file on your PC, by double-clicking it. If your file associations are set up correctly, the application that"s meant to open your .log file will open it. It"s possible you may need to download or purchase the correct application. It"s also possible that you have the correct application on your PC, but .log files aren"t yet associated with it. In this case, when you try to open a .log file, you can tell Windows which application is the correct one for that file. From then on, opening a .log file will open the correct application.

applications that open a .log file

Notepad2

The Notepad2 application is a more advanced text editor for Windows developed by Florian Balmer. This program originated from the original built-in Microsoft Notepad which is why it is also effective and fast even when it is small. Notepad2 also has a lot of features such as syntax highlighting that allows a text or a source code to be displayed using different fonts and colors. This syntax highlighting feature of notepad2 allows users to write programming language easily and clearly. This amazing function of Notepad2 is also owing to several other features it possess such as auto indentation, regular and expression-based find and replace feature, bracket matching, newline conversion, encoding conversion as well as multiple undo and redo features. These features make the function of the simple Notepad more advanced and it makes Notepad more interesting to use either to open files in .txt format or to write HTML codes. Notepad2 also supports many programming languages ​​such as ASP, C++, Perl, Java, etc.

Microsoft Notepad

Microsoft Notepad

Notepad is a basic text editor used to create plain documents. It is commonly used to view or edit text (.txt) files, and a simple tool for creating Web pages, and supports only the basic formatting in HTML documents. It also has a simple built-in logging function. Each time a file that initializes with .log is opened, the program inserts a text timestamp on the last line of the file. It accepts text from the Windows clipboard. This is helpful in stripping embedded font type and style codes from formatted text, such as when copying text from a Web page and pasting into an email message or other “What You See Is What You Get† text editor. The formatted text is temporarily pasted into Notepad, and then immediately copied again in stripped format to be pasted into the other program. Simple text editors like Notepad may be used to change text with markup, such as HTML. Early versions of Notepad offered only the most basic functions, such as finding text. Newer versions of Windows include an updated version of Notepad with a search and replace function (Ctrl + H), as well as Ctrl + F for search and similar keyboard shortcuts. It makes use of a built-in window class named edit. In older versions such as Windows 95, Windows 98, Windows Me and Windows 3.1, there is a 64k limit on the size of the file being edited, an operating system limit of the EDIT class.

Microsoft Works

Microsoft Works

Microsoft Works is incorporated package software that was developed by Microsoft. It is less expensive, smaller, and has fewer features than Microsoft Office or other office suites. Its central functionality includes a word processor, a spreadsheet and a database management system. Newer versions have a calendar application and a dictionary while older versions included a terminal emulator. Files with WPS extension is utilized for output files of the Microsoft Works word processing application. These files are classified as text documents that can be created, saved, viewed and edited using the Microsoft Works program. Microsoft Word 2010, Microsoft Publisher 2010, Planamesa NeoOffice, and OxygenOffice Professional are some of the applications that are able to open and view the content of these WPS files. The contents of these WPS files can also be exported to other compatible word document formats. This promotes convenience and efficient document presentation, group collaboration and sharing between users of different systems and word processing applications; however, WPS document cannot be applied with macros and other formatting options available in Microsoft Word; so Microsoft discontinued support and development of the Microsoft Works application with its version 9 and the release of Microsoft Word 2010.

Microsoft Word

Microsoft Word is a word processor program that is packed in the Microsoft Office Suite. It is developed by Microsoft Corporation, generating a .doc file extension when the file is saved. A document file format (.doc) is a text or binary file format for saving documents on a storage media, mainly for computer use, like typing text, charts, tables, page formatting, graphs, images and other documents whose content is created and edited. Contents of these documents are printable in any sizes and are capable of opening in other devices provided that its operating system is able to read DOC files. This .doc file extension has become extensive de facto standard for office documents, but it is an owned format and is not always totally supported by other word processors. A variety of programs that is able to open this type of file, and different operating systems and have installed programs that can open a 1ST file are: Microsoft Word, Microsoft Notepad, Microsoft Word, IBM Lotus WordPro, and Corel WordPerfect.

Microsoft WordPad

a word of warning

Be careful not to rename the extension on .log files, or any other files. This will not change the file type. Only special conversion software can change a file from one file type to another.

what is a file extension?

A file extension is the set of three or four characters at the end of a filename; in this case, .log. File extensions tell you what type of file it is, and tell Windows what programs can open it. Windows often associates a default program to each file extension, so that when you double-click the file, the program launches automatically. When that program is no longer on your PC, you can sometimes get an error when you try to open the associated file.

FIX .log FILE ASSOCIATION ERRORS

Find and fix file extension errors, registry problems and restore optimum PC performance quickly, easily and safely.

Try Registry Reviver® Free.

Start Download

leave a comment

Please enable JavaScript to view the comments powered by Disqus.

LOG format files open special programs. There are 2 types of LOG formats, each of which opens different programs. To open desired type format, study the file descriptions and download one of the proposed programs.

.LOG file extension

System log used by various operating systems and programs. Typically contains a simple text log of specific events and their timestamps. Can be created operating system to monitor events or the installer to list the locations and names of installed files.

Web servers also create log files to track visitors and monitor usage bandwidth. Web statistics programs allow web repositories to analyze system log files through charts and graphs that present website traffic data in a graphical format.

Download the program for LOG format

Virus scan report generated by antivirus program AntiVir for Windows. Stored in plain text format and contains a system log of antivirus scans or program updates. Used to store the history of antivirus operation.

AntiVir LOG files can be viewed in the Overview → Reports panel, which displays a list of reports. Open a report in this panel and click on the Report button to open the file.