how to check 400 files exist

[lina <lina.lastname@gmail.com>]

Hi,

Thanks ahead for reading this email.

I am choked by how to check more than 400 files exist or not, if not,
sleep, but once it's all generated, continue do something.

for i in $(seq 5); do if [ -e sys_em_$i.txt ] ; then echo done ; fi ;
done not work.

those files have a common feature:

sys_em_$i.txt

Thanks for any advice,

Best wishes,