This command will generate a random number between 10 and 9999 and then format it as a string with underscores, hyphens, and colons. For example, if the random number is 1234, the output will be 1_2-3:4.
shuf -i 10-9999 -n 1 | xargs -I {} printf "echo {}\n" | sed 's/./&_/3;s/./&-/2;s/./&:/1' | sh