After writing a script, how do you execute it on the command line ie on the terminal.

first make it executable: chmod
usually cd to directory

#./NAME_OF_SCRIPT

1. As it was already mentioned, make it executable and execute then:
2. Without making executable. Assuming that the first line of your script is #!/bin/bash:

adding terminology info, #!/bin/bash this section called shebang and it has many synonym

http://en.wikipedia.org/wiki/Shebang_%28Unix%29

I'd recommend only
Don't go handing out execute privs to the world....
http://linux.die.net/man/1/chmod

always try to add the following at the top in your script, it helps to find which command should be used to sun the script when you run the command ./script_name

For perl :
#!/usr/bin/perl
For bash :
#!/bin/bash

if you want to run a shell script there are two ways :
sh script_name

or change the file permission via chmod and run directly
./script_name

Oops. piyush.sharma already covered this!

You can also do sh yourscript.sh.

I was a-dither with excitement when I read about that.

How about pulling up a good online tutorial and working through it, instead of asking? Tutorials generally start with a section on how to set up and launch a script.

Here are a few useful bash scripting references:
http://mywiki.wooledge.org/BashGuide
http://www.linuxcommand.org/index.php
http://mywiki.wooledge.org/BashFAQ
http://mywiki.wooledge.org/BashPitfalls
http://wiki.bash-hackers.org/scripting/newbie_traps
http://tldp.org/LDP/Bash-Beginners-G...tml/index.html
http://www.tldp.org/LDP/abs/html/index.html
http://www.gnu.org/software/bash/manual/bashref.html
http://wiki.bash-hackers.org/start
http://ss64.com/bash/


I recommend the bashguide and linuxcommand as good starting pages.

BTW, note that when you run a script with "sh script_name", any shebang in it is ignored (since it starts with a "#" comment character). A new shell session is first opened, and the lines in the file are simply executed one after the other. The shebang only has a special function if the script is executed directly.

Also be aware that /bin/sh is not the same as /bin/bash. While bash may be set up as the interpreter for sh, it also may not be, and even if it is, the shell any script executed with "sh" is interpreted according to posix-compliant syntax. Shell-specific features may or may not work as expected.