MySQL export tables with prefix from Unix command line
You have to generate the list of tables you want to dump then act upon it.
mysql -u USER -p -D test -Bse "show tables like 'wiki_%'" >tables.out
mysqldump -u USER -p test <tables.out >wiki_tables.dump
or as a one liner
mysqldump -u USER -p test $(mysql -u USER -p -D test -Bse "show tables like 'wiki_%'")
but you still get to enter the password twice.