Skip to main content

LINUX Viewing text files from the shell prompt

The head Command

head <filename>
By default, you can only read the first ten lines of a file.You can change the 
number of lines displayed by specifying a number option. 
head -20 <filename>

The tail Command 

The reverse of head is tail. Using tail, you can view the last ten lines of a file. This can be useful for viewing the last ten lines of a log file for important system messages. You can also use tail to watch log files as they are updated. Using the -f option, tail automatically prints new messages from an open file to the screen in real-time. For example, to actively watch /var/log/messages, enter the folowing at a shell prompt (as the root user):  
tail -f /var/log/messages
Press[Ctrl]-[C] when you are finished. 
Viewing Files with less
The format of the less command is:
less <filename>
The main difference between more and  less is that less allows  backward and single-line movement using the same navigation as  man pages: press the [Space] bar to go down one  page, the [B] to go back one page, the  directional (or "arrow") keys to move one line at a  time, and [Q] to quit.
To search the output of a text file using  less, press [/] and  enter the keyword to search for within the file.
/stuff







































Comments











Post a Comment






























Popular posts from this blog



















PERL Some good framework




























1. Catalyst is the most popular agile Perl  MVC web framework  that encourages rapid development and clean design without getting in your way. Catalyst | Perl  MVC web application framework 2. Mojolicious is a next generation web framework  for the Perl  programming language. Back in the early days of the web, many people learned Perl  because of a wonderful Perl   ... Mojolicious - Perl  real-time web framework 3. Documents for Perl  The Perl Archive Network, the gateway to all things Perl. The canonical location for Perl code and modules. The Comprehensive Perl Archive Network  - www. cpan .org




















Post a Comment









Read more




























C++ How to use Date and Time




























The C++ standard library does not provide a proper date type. C++  inherits the structs and functions for date and time manipulation from  C. To access date and time related functions and structures, you would  need to include <ctime> header file in your C++ program.  There are four time-related types: clock_t, time_t, size_t , and tm . The types clock_t, size_t and time_t are capable of representing the system time and date as some sort of integer.  The structure type tm  holds the date and time in the form of a C structure having the following elements:  struct  tm {   int  tm_sec ;    // seconds of minutes from 0 to 61   int  tm_min ;    // minutes of hour from 0 to 59   int  tm_hour ;   // hours of day from 0 to 24   int  tm_mday ;   // day of month from 1 to 31   int  tm_mon ;    // month of year from 0 to 11   int  tm_year ;   // year since 1900   int  tm_wday ;   // days since sunday   int  tm_yday ;   // days since January 1st   int  tm_isdst ;  // hours of daylight savin...




















Post a Comment









Read more






























Lambda Function with Amazon DynamoDB




























DynamoDB can trigger AWS Lambda when the data in added to the tables, updated or deleted. In this chapter, we will work on a simple example that will add items to the DynamoDB table and AWS Lambda which will read the data and send mail with the data added. Requisites To use Amazon DB and AWS Lambda, we need to follow the steps as shown below − Create a table in DynamoDB with primary key Create a role which will have permission to work with DynamoDBand AWS Lambda. Create function in AWS Lambda AWS Lambda Trigger to send mail Add data in DynamoDB Let us discuss each of this step in detail. Example We are going to work out on following example which shows the basic interaction between DynamoDB and AWS Lambda. This example will help you to understand the following operations − Creating a table called customer in Dynamodb table and how to enter data in that table. Triggering AWS Lambda function once the data is entered and sending mail using Amazon SES service. The basic block diagram that ...




















Post a Comment









Read more