Question

i run this script from the command line:

check_databse_exist=`mysql -u root --password=root -Bse 'show databases' | egrep -v 'information_schema|mysql'`
for db in $check_databse_exist; do
if [ "$db" == "test_traffic" ] ; then
   exist=1
fi
done

if [ $exist -eq 1 ] ; then
   #do other stuff
fi

exit 0

why is it giving:

 [: 16: jobeet: unexpected operator
 [: 16: jobeet_test: unexpected operator
 [: 16: landpage_db: unexpected operator
 [: 16: my_db: unexpected operator
 [: 16: symfony2: unexpected operator
 ./cibuild: 24: [0: not found

i just want to loop and if found set exist = 1
thanks

Answer 1

if [$exist == 1] ; then

Due to a shell scripting quirk you need spaces around the square brackets. They’re not optional.

if [ $exist == 1 ]; then

For what it’s worth, you could refactor this a bit if you merely want to check for the existence of one table, and don’t otherwise need $check_databse_exist. The idea would be to to replace the for loop with a grep.

if mysql -u root --password=root -Bse 'show databases' | grep -qw test_traffic; then
    # Database exists.
fi

grep -q produces no output, it merely returns success or failure. grep -w is optional but a good practice; it prevents a table like test_traffic2 from matching.