Wget is a very cool command-line downloader for Linux and UNIX environments. Don\u2019t be fooled by the fact that it is a command line tool. It is very powerful and versatile and can match some of the best graphical downloaders around today. It has features such as resuming of downloads, bandwidth control, it can handle authentication, and much more. I\u2019ll get you started with the basics of using wget and then I\u2019ll show you how you can automate a complete backup of your website using wget and cron.<\/p>\n
Let\u2019s get started by installing wget. Most Linux distributions come with wget pre-installed. If you manage to land yourself a Linux machine without a copy of wget try the following. On a Red Hat Linux based system such a Fedora you can use:<\/p>\n
# yum install wget<\/p>\n
or if you use a Debian based system like Ubuntu:<\/p>\n
# sudo apt-get install wget<\/p>\n
One of the above should do the trick for you. Otherwise, check with your Linux distribution\u2019s manual to see how to get and install packages. wget has also been ported to Windows. Users on Windows can access this website. Download the following packages: ssllibs and wget. Extract and copy the files to a directory such as C:\\Program Files\\wget and add that directory to you system\u2019s path so you can access it with ease. Now you should be able to access wget from your Windows command line.<\/p>\n
The most basic operation a download manager needs to perform is to download a file from a URL. Here\u2019s how you would use wget to download a file:<\/p>\n
# wget http:\/\/www.sevenacross.com\/photos.zip<\/p>\n
Yes, it\u2019s that simple. Now let\u2019s do something more fun. Let\u2019s download an entire website. Here\u2019s a taste of the power of wget. If you want to download a website you can specify the depth that wget must fetch files from. Say you want to download the first level links of Yahoo!\u2019s home page. Here\u2019s how would do that:<\/p>\n
# wget -r -l 1 http:\/\/www.yahoo.com\/<\/p>\n
Here\u2019s what each options does. The -r activates the recursive retrieval of files. The -l stands for level, and the number 1 next to it tells wget how many levels deep to go while fetching the files. Try increasing the number of levels to two and see how much longer wget takes.<\/p>\n
Now if you want to download all the \u201cjpeg\u201d images from a website, a user familiar with the Linux command line might guess that a command like \u201cwget http:\/\/www.sevenacross.com*.jpeg\u201d would work. Well, unfortunately, it won\u2019t. What you need to do is something like this:<\/p>\n
# wget -r -l1 \u2013no-parent -A.jpeg http:\/\/www.sevenacross.com<\/p>\n
Another very useful option in wget is the resumption of a download. Say you started downloading a large file and you lost your Internet connection before the download could complete. You can use the -c option to continue your download from where you left it.<\/p>\n
# wget -c http:\/\/www.sevenacross.com\/ubuntu-live.iso<\/p>\n
Now let\u2019s move on to setting up a daily backup of a website. The following command will create a mirror of a site in your local disk. For this purpose wget has a specific option, \u2013mirror. Try the following command, replacing http:\/\/sevenacross.com with your website\u2019s address.<\/p>\n
# wget \u2013mirror http:\/\/www.sevenacross.com\/<\/p>\n
When the command is done running you should have a local mirror of your website. This make for a pretty handy tool for backups. Let\u2019s turn this command into a cool shell script and schedule it to run at midnight every night. Open your favorite text editor and type the following. Remember to adapt the path of the backup and the website URL to your requirements.<\/p>\n
#!\/bin\/bash<\/p>\n
YEAR=`date +\u201d%Y\u201d`
\n MONTH=`date +\u201d%m\u201d`
\n DAY=`date +\u201d%d\u201d`<\/p>\n
BACKUP_PATH=`\/home\/backup\/` # replace path with your backup directory
\n WEBSITE_URL=`http:\/\/www.sevenacross.net` # replace url with the address of the website you want to backup<\/p>\n
# Create and move to backup directory
\n cd $BACKUP_PARENT_DIR\/$YEAR\/$MONTH
\n mkdir $DAY
\n cd $DAY<\/p>\n
wget \u2013mirror ${WEBSITE_URL} <\/p>\n
Now save this file as something like website_backup.sh and grant it executable permissions:<\/p>\n
# chmod +x website_backup.sh<\/p>\n
Open your cron configuration with the crontab command and add the following line at the end:<\/p>\n
0 0 * * * \/path\/to\/website_backup.sh<\/p>\n
You should have a copy of your website in \/home\/backup\/YEAR\/MONTH\/DAY every day. For more help using cron and crontab, see this tutorial.<\/p>\n
There\u2019s a lot more to learn about wget than I\u2019ve mentioned here. Read up wget\u2019s man page.<\/p>\n","protected":false},"excerpt":{"rendered":"
Wget is a very cool command-line downloader for Linux and UNIX environments. Don\u2019t be fooled by the fact that it is a command line tool. It is very powerful and versatile and can match some of the best graphical downloaders around today. It has features such as resuming of downloads, bandwidth control, it can handle… <\/p>\n