Can I easily search my history across many screen windows?

My current screen session has 12 open windows on it. It’s been running for weeks… I know I executed an ImageMagick convert command in one of these 12 screen windows sometime last week… is there any way I can easily search through the Bash history of all 12 instances, without closing them or running history | grep convert in all 12 screens?

Run script in a screen

I want to run a bash script in a detached screen. The script calls a program a few times, each of which takes too long to wait. My first thought was to simply open a screen and then call the script, but it appears that I can’t detach (by ctrl-a d) while the script is running. So I did some research and found this instruction to replace the shebang with following: