One thing that is absent from curl is the ability to handle errors. That is where bash comes in handly. Curl has an—retry NUM option that as you may have guess tells curl to retry a specific number of times. However, what if we want to have curl effectively retry indefinitely until succeeding? Source: curl-retry. The hope is that eventually someone will create temptemp3.
Last but not least I would like to end with an example of how to set up concurrent curls in bash to act as a download accelerator. Sometimes it is helpful to download large files in parts. Here is a snippet from a bash script that I wrote recently using curl. Source: downldr. By this time you are killing it with curl in bash scripts. In many cases you may take advantage of curl functionality through the horde of options it provides.
However, you may opt out and achieve the same functionality outside of curl in bash for the level of control that fits your needs. A developer and advocate of shell scripting and vim. His works include automation tools, static site generators, and web crawlers written in bash. For work he tools with cloud computing, app development, and chatbots.
Not very surprising, really. This is obviously silly, since without using external utilities, there's not much we can do with the downloaded file, not even make it executable. So you can also use SSH to upload to it. Which is functionally equivalent to downloading of software packages etc.
As shown in this answer , you would execute the following on your local machine to place a file on your remote headless server:. The disadvantage of the above solution compared to downloading is lower transfer speed, since the connection with your local machine usually has much less bandwidth than the connection between your headless server and other servers. To solve that, you can of course execute the above command on another server with decent bandwidth.
To make that more comfortable avoiding a manual login on the third machine , here is a command to execute on your local machine. See the explanations below for the reason. The command will ssh to your third machine intermediate-host , start downloading a file to there via wget , and start uploading it to target-host via SSH.
Downloading and uploading use the bandwidth of your intermediate-host and happen at the same time due to Bash pipe equivalents , so progress will be fast.
For the -T -e none SSH options when using it to transfer files, see these detailed explanations. This command is meant for cases where you can't use SSH's public key authentication mechanism — it still happens with some shared hosting providers, notably Host Europe.
To still automate the process, we rely on sshpass to be able to supply the password in the command. It requires sshpass to be installed on your intermediate host sudo apt-get install sshpass under Ubuntu. We try to use sshpass in a secure way, but it will still not be as secure as the SSH pubkey mechanism says man sshpass.
In particular, we supply the SSH password not as a command line argument but via a file, which is replaced by bash process substitution to make sure it never exists on disk.
The printf is a bash built-in, making sure this part of the code does not pop up as a separate command in ps output as that would expose the password [ source ]. And that without using a temp file [ source ]. But no guarantees, maybe I overlooked something. Again to make the sshpass usage safe, we need to prevent the command from being recorded to the bash history on your local machine.
In this example, we will download the latest Debian ISO. After executing the command above, you will see a progress bar appear in the terminal. When the progress bar goes away, the file is done downloading. Like Wget, the Curl app supports download lists. First, start by creating the download-list file with the touch command below. Paste the URLs you wish to download into the download-list file.
After that, use the command below to have Curl download from the list. To customize the download location, follow the example below. For this purpose wget has a specific option, —mirror.
Try the following command, replacing sevenacross. When the command is done running you should have a local mirror of your website. This make for a pretty handy tool for backups. Open your favorite text editor and type the following. Remember to adapt the path of the backup and the website URL to your requirements. Open your cron configuration with the crontab command and add the following line at the end:.
For more help using cron and crontab, see this tutorial. At this present Internet-based generation, every individual living in the world tend to take more pictures with their smartphone and cameras. Image Downloader Softwares are the quickest and the most convenient solution to download any number of picture and video related files from the online sources.
The following are some of the softwares that are highly used by many users from all over the world to download bulk images from web pages. The Free Image Downloader is a freeware version that can extract the image files from a specified URL link that the user provides inside the software with.
The user simply needs to copy and paste the website URL in which they are in need of images to download from. The Free Image Downloader extracts the links and shows the pictures that can be downloaded to your computer. This image downloading software can help you in extracting the links to download your favorite wallpapers, photos, mp3s and videos from a web page. The major plus point of using this software is that, it grabs the links to download all the needed images and videos for the user automatically.
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I have a URL from which I have to download data on daily basis, e. In the above URL, it gives me data for 17th May Similarly for the data of 18th May , URL will be: www. Please help me how to do it. I want to add this job on cron also, so that I don't need to manually run the code. You have two bits here. The command to put up here is : wget www.
You can put this command in a daily cron to download the files in a daily basis.
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