Depending on the type of shell you can execute a file in 
either of the ways
1) ksh <filename>
2) sh <filename>
If the file already possess execute bit set on it, then you 
can directly execute the file with its name alone
1) <filename>

if the file doesn't have executable permissions than assign 
the same as chmod 755 <filename>. after that execute the 
same by using command ./<filename>

Yes the above answer is absolutely apt.

chmod - R 755 foldername

sudo chmod +x filename
./filename

There are lot of ways by which u can execute a file in Unix.

1. ./<filename>

2. <filename> #only if the permissions are in place for the 
user

3. sh <filename> #uses bash shell

4. nohup <filename> #the process doesn't get killed even on 
reboot

5. Batch <filename>

6. at <time> <filename> #to schedule the job 

7. U can also autorun it by making an entry into the cron