symbolic links, aliases, cls clear

[Pankaj]

its true for the processes, gone to the system mode and from there the
process is not considering the shell variable any more.

In case of deamons also it is the same case. For Phython programs, I am
not sure , may they are also nohops, so might be not accessing the
shell variables. But i think you have defined the alias to some other
place.... the error is reported by shell that cls not found.

This could be investigated if you do some tests with the system. Like
alias is shell script you can open it and read it , how it invokes the
command for creating aliases. etc etc.

Alias: When the shell is in picture it directly replaces the string
"cls" to "clear" and execute the clear.

Symbolic links: are reference to the inode of the actual files, so it
should work in your case.

just run
#which clear
(O/P , you will get the location of binary say /usr/bin/clear)

Now you can create the symbolic link named as cls at location
"/usr/bin". this symbolic link should be a soft link to /usr/bin/clear.
 you can also put the symbolic links to any of the location that is
displayed by $PATH variable.

for any command you execute in shell, it functions in following order:
(Not exactly the same, need to confirm, i might miss some of the steps)

1) check with the shell variable(whether any alias to this command
exists or not!)
2) search it in the locations $PATH and execute the command is it is
found.
so on...