csh scripting for password authorisation of user
I'm trying to write a professional program to accept and process input via a Menu based system. The program should have no command line arguments. it will be writen in csh script called TaskMenu开发者_C百科. This shell script will:
- ask for a password from the user. a. If the password is not correct, the system will exit with an appropriate error message.
- display a text menu and then get a response from the user.
- process the user input and redisplay the text menu until the user wants to quit.
To read a password, turn echo off, read the password, then re-enable echo. csh:
stty -echo
echo -n "Enter password: "
set password = $<
stty echo
To create a menu, just echo the choices to the screen, then read a value back. csh:
echo 1 first item
echo 2 second item
echo 3 third ...
echo -n "Enter Choice: "
set choice = $<
These same two tasks in bash are:
Read password:
echo -n "Enter password: "
read -s password
Make menu:
select choice in "first item" "second item" "third..." do
test -n "$choice" && break;
done
Notice how reading a password and making a menu are built-in to bash. In addition to being easier, some common things done in scripting are impossible in csh. Csh is not designed as a scripting language. It is much easier to use Bash, Python, Ruby, Perl or even the lowly /bin/sh for scripting anything over a few lines.
That said, here is a full csh script showing the password and menu methods:
#! /bin/csh
set PW="ok"
### Read Password
echo -n "enter passwd: "
stty -echo
set passwd = $<
stty echo
if ( "$passwd" == "$PW" ) then
echo Allrighty then!
else
echo "Try again. Use '${PW}'."
exit 1
endif
### Menu
@ i = 1
set items = (one two three four five six seven)
foreach item ( $items[*] )
echo "${i}) $item"
@ i = $i + 1
end
set choice = 0
while ( $choice < 1 || $choice > $#items )
echo -n "Select: "
set choice = $<
end
echo "You chose ${choice}: $items[$choice]"
Notes
Though popular for interactive use because of its many innovative features, csh has never been as popular for scripting[1]
1 Wikipedia
Q: Why in the heck would anybody want to use csh in a bash world ;) csh is Soooo 1985 ;)
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