How to download images sequentially from a website using Wget?

Question

I need to know where the error in the command is:

 wget http://shadowera.com/cards/se{001..200}.jpg

I used the "shadowera" website for testing. I need to know how to save multiple images at once, and that way it’s not working.

Answer 1

Solution

Before using this loop, type cmd /v in the console to enable parameter expansion:

set i=1000 && for /l %a in (1,1,200) do (
   set /a "i=!i!+1" && wget http://shadowera.com/cards/se!i:~1,3!.jpg )

Line break is for easy reading only.

Explanation

As we are using the CMD, and not a Shell, the expansion {001..200} does not work. The solution found was a for.

for /l %a in (1,1,200) do ( ...comandos... )

The initial problem is that the maximum one for normal CMD would give us, would be a count from 1 to 200, and not from 001 to 200, which is the required output for the problem, given that the files are se001.jpg to se200.jpg, and not se1.jpg onward.

So the simple solution would be to count from 1001 to 1200 and take advantage of the last three digits only. For this, the initial idea would be to use CMD substrings:

%variavel:~posicaoinicial,final%

Since nothing is simple, unfortunately the CMD substrings only work for "conventional" environment variables, and do not apply to the for, %a in the case.

For this, we use an additional variable, i, starting with 1000, and increasing it during the loop. To keep everything in one line, we use the && (and) to concatenate commands.

set i=1000 && ..for.. ( set /a "i=%i%+1 ..

But... this doesn’t work!

It does not work because the assignment of sets is done first, and it will execute the next command with the wrong values.

The solution: start a CMD with flag /V, that activates the delayed expansion of the variable, which solves our problem. For this we use the format !variavel! in place of %variável%

The result is the compound command from the beginning of the response.