Remove every other frame & slow down gif animation in Linux

trim_slow_gif.txt

#Get the number of frames from the gif: 
identify -format "%n\n" path/to/file.gif | head -1
#Use gifsicle to cut frames. replace 99 with total frames. 
gifsicle -U input.gif `seq -f "#%g" 0 2 99` -O2 -o output.gif

#Delay gif via gifsicle by first finding the delay between frames, double it
gifsicle -I input.gif
#Proceed to delay. Replace 50 with the doubled number
gifsicle --delay 50 in.gif > out.gif

#Alt method: Delay with Imagemagick
#First list all frame delays:
identify -verbose your.gif | grep Delay
#double the first number Ex: 5x100 -> 10x100
#slow down the gif:
convert -delay <NewDelay> your.gif your_slow.gif


#For more info:
#https://graphicdesign.stackexchange.com/questions/20908/how-to-remove-every-second-frame-from-an-animated-gif