Μηνιαία αρχεία: Απρίλιος 2016

Ubuntu/Bash: Get the IP of eth0

 στο Bash / GNU/Linux  επισημασμένο με ετικέτα bash / IP / ubuntu Από

Following is a small snippet that will print on screen the IP of eth0 while in Ubuntu (Both server and desktop versions).
As you will see, it is not a very sound solution as it depends on the structure of the output of ifconfig eth0.

Nevertheless is works (for Ubuntu at least)! 🙂

ifconfig eth0 | grep "inet addr" | cut -d ':' -f 2 | cut -d ' ' -f 1

What this line does is: first it prints out the configuration information for eth0, then finds the line that contains the inet addr, using cut it gets the second column of the data after separating the line using the : symbol. Right now in the pipe we will have something similar to this 192.168.1.37 Bcast, so we need to filter out the last part as well. We do the last filtering by using cut again, this time by getting the first column while using the space character as the delimiter.

The Ubuntu version that was used for this tutorial is

$lsb_release -a
No LSB modules are available.
Distributor ID:	Ubuntu
Description:	Ubuntu 14.04.4 LTS
Release:	14.04
Codename:	trusty

The version of ifconfig for this tutorial is

$ifconfig --version
net-tools 1.60
ifconfig 1.42 (2001-04-13)

In case you want to assign the IP of eth0 to a variable, you can easily do as follows

ETH0=`ifconfig eth0 | grep "inet addr" | cut -d ':' -f 2 | cut -d ' ' -f 1`;

Batch convert NEF photos to JPEG using ufraw

 στο Applications  επισημασμένο με ετικέτα Batch / convert / JPEG / NEF / ufraw Από

ufraw converts camera RAW images to standard image files (like jpeg).
Using the ufraw-batch we can massively convert the images in a folder in one call without the need of external scripts to invoke each separate call.

ufraw-batch --out-type=jpeg --out-path=./ ./*.NEF

In the above example we set the output type to jpeg, the folder to write the new images the one we are currently in (./) and the input all NEF files in the current folder.

Batch resize images using ImageMagick

 στο Applications / Bash / GNU/Linux  επισημασμένο με ετικέτα convert / imagemagick / resize Από

The following command will make a shrink copy of all images with the extension jpg in the current folder. The new images will have the 20% of their original size and will have the prefix re_.

for i in $( ls *.jpg ); do convert -resize 20% $i re_$i; done

You need to have ImageMagick installed to get this feature.

Automatically download possibly a whole public website using wget recursively

 στο Bash / GNU/Linux  επισημασμένο με ετικέτα download / full site / recursive / wget Από 
wget -r -k -np --user-agent="Mozilla/5.0 (iPhone; CPU iPhone OS 7_0 like Mac OS X; en-us) AppleWebKit/537.51.1 (KHTML, like Gecko) Version/7.0 Mobile/11A465 Safari/9537.53" --wait=2 --limit-rate=200K --recursive --no-clobber --page-requisites --convert-links --domains bytefreaks.net https://bytefreaks.net/;

Introduction:

The “wget” command is a powerful tool used to download files and web pages from the internet. It is commonly used in Linux/Unix environments but can also be used on other operating systems. The command comes with various options and parameters that can be customized to suit your specific download requirements. In this post, we will discuss the wget command with a breakdown of its various options, and how to use it to download files and web pages.

Command Explanation:

Here is a detailed explanation of the options used in the command:

  1. “-r” : This option is used to make the download recursive, which means that it will download the entire website.
  2. “-k” : This option is used to convert the links in the downloaded files so that they point to the local files. This is necessary to ensure that the downloaded files can be viewed offline.
  3. “-np” : This option prevents wget from ascending to the parent directory when downloading. This is helpful when you want to limit the download to a specific directory.
  4. “–user-agent” : This option allows you to specify the user agent string that wget will use to identify itself to the server. In this case, the user agent string is set to a mobile device (iPhone).
  5. “–wait” : This option adds a delay (in seconds) between requests. This is useful to prevent the server from being overloaded with too many requests at once.
  6. “–limit-rate” : This option is used to limit the download speed to a specific rate (in this case, 200K).
  7. “–recursive” : This option is used to make the download recursive, which means that it will download the entire website.
  8. “–no-clobber” : This option prevents wget from overwriting existing files.
  9. “–page-requisites” : This option instructs wget to download all the files needed to display the webpage, including images, CSS, and JavaScript files.
  10. “–convert-links” : This option is used to convert the links in the downloaded files so that they point to the local files. This is necessary to ensure that the downloaded files can be viewed offline.
  11. “–domains” : This option allows you to specify the domain name(s) that you want to download.
  12. “https://bytefreaks.net/” : This is the URL of the website that you want to download.

Conclusion:

The wget command is a powerful tool that can be used to download files and web pages from the internet. By using the various options and parameters available, you can customize your download to suit your specific requirements. In this post, we have discussed the wget command and its various options, and how to use it to download files and web pages. We hope that this post has been helpful and informative, and that it has given you a better understanding of the wget command.

Same command without setting the user agent:

The following command will try to download a full website with all pages it can find through public links.

wget --wait=2 --limit-rate=200K --recursive --no-clobber --page-requisites --convert-links --domains example.com http://example.com/;

Parameters:

  • --wait Wait the specified number of seconds between the retrievals.  We use this option to lighten the server load by making the requests less frequent.
  • --limit-rate Limit the download speed to amount bytes per second. We use this option to lighten the server load and to reduce the bandwidth we consume on our own network.
  • --recursive Turn on recursive retrieving.
  • --no-clobber If a file is downloaded more than once in the same directory, we prevent multiple version saving.
  • --page-requisites This option causes Wget to download all the files that are necessary to properly display a given HTML page.
  • --convert-links After the download is complete, convert the links in the document to make them suitable for local viewing.
  • --domains Set domains to be followed.  It accepts a domain-list as a comma-separated list of domains.