Bash: Failed retrieval while using pipeline substitution for gifsicle

Question

I'm currently trying to write a program that uses wget to grab 3 files from the internet and merge them into a gif. Because I'm trying to avoid having temporary files I'm attempting to use pipeline substitution to solve this, however whenever I run the program I get the messages:

"gifsicle:/dev/fd/63: empty"

"gifsicle:/dev/fd/62: empty"

"gifsicle:/dev/fd/61: empty"

Below is the command in question:

gifsicle -d 100 -l <(wget https://www.wpc.ncep.noaa.gov/basicwx/91fndfd_loop.gif -O /dev/null) <(wget https://www.wpc.ncep.noaa.gov/basicwx/92fndfd_loop.gif -O /dev/null) <(wget https://www.wpc.ncep.noaa.gov/basicwx/93fndfd_loop.gif -O /dev/null) -o $1

Answer 1

You are actively sending the the output of the cURL commands to /dev/null!!! It is obviously complaining about this. Send it to stdout instead:

gifsicle -d 100 -l <(wget https://www.wpc.ncep.noaa.gov/basicwx/91fndfd_loop.gif -O -) <(wget https://www.wpc.ncep.noaa.gov/basicwx/92fndfd_loop.gif -O -) <(wget https://www.wpc.ncep.noaa.gov/basicwx/93fndfd_loop.gif -O -) -o $1