Shell Programming and Scripting

Hello Friends,

I am facing problem in creating aliases.

I am working in SunOS 5.10. When I login in system i have been given ksh shell.

What i am doing is that ?

I am changing shell to bash then I am creating 2 alias in command prompt like:

Code:

alias deploy_dir=' cd /opt/home/deploy/'
alias log_dir=' cd /opt/home/javalogs/'

It is working fine in command prompt. But when kept these 2 cmds in shell script and executed it gives error like:
myalias.sh:

Code:

#!/bin/bash
alias deploy_dir=' cd /opt/home/deploy/'
alias log_dir=' cd /opt/home/javalogs/'

Scripts run successfully but when i tried to type:
bash-3.00$ deploy_dir
bash: deploy_dir: command not found
bash-3.00$ log_dir
bash: log_dir: command not found

Please suggest what is wrong?

Thanks
Krsna

Hi

You should source the script, not run the script like a command.

if in bash:

Code:

$ source script_name

for ksh:

Code:

 . scriptname

Moreover, the script may not help you much since the default shell is ksh.

i) do not put the #!/bin/bash line in the script
ii) since the default is ksh, run the script like:

Code:

  . scriptname

Guru

Hi Guru,

Many thanks, it is resolved by your solution. I have question for my understanding..

1. using

Code:

source

means we are running script in same shell. Generally what should be right way to run script, in same shell or in parent shell?

2. If i need to run script usng bash then why can i not put . As i can see one the vendor provided script we have which start the tomcalt server using this entry...

Code:

#!/bin/bash

we run that using ./starttomcat.sh..

Thanks..

Hi

1) When you have a script which contains commands like aliases or setting environment variables, we usually want them to get reflected in the current shell. In these cases, we use source. This is why always the profile files and aliases are run using the . or source.

2) If you put the shebang(#!/bin/bash) in the script, you are telling the OS to run the script using the shell mentioned in the first line (which in this case is bash). The moment this happens, your aliases are not going to work since this is not run in the same shell. Moreover, alias syntax is not the same across all shells. In case of your vendor script, it is just like any other shell script, not some shell specific settings, which is why the shebang line is present.

Hope this helps.

Guru

Great ,

Thank you so much..