Shell Programming and Scripting

Hi

Code:

echo " username "
read username
echo "password"
stty -echo
read password
stty echo

through read i am taking standard input and redirecign them to a file

Code:

echo " username=${username}/${password} " > file.lst

now from the same shell script i want to delete the password (i.e ${password}) so that no body can see my pssword

i tried this

Code:

sed -i 's/\$password//g' file.lst

this is not working.. is there any suggestion how can i delete the password from redirected file.lst ?

Dont escape the $password.
That is, because the file will not contain the variable name, but the value, so, sed requires the value too.

Escaping the variable, makes sed reading the escaped $, rather than to translate the variable to its value, which here is required.

hth

PS:
Please use code tag for code blocks in your further posts.

EDIT:
Even simpler, dont write the password to the file

Thanks .. Yes you are right.. i dopped that options to save pwd in file.. however unmasking $ also did not worked.. thanks for your suggetion.

Leaving such in the environment is more secure.

Code:

export XX_ID=my_XX_id XX_PW=my_XX_password

XX being whatever you want to call it.

As has already been stated, you don't want to escape the $, but even after you fix that, variables aren't expanded inside single quotes. If you can't pass the variables through the environment as suggested by DGPickett, your sed command might work if you use double quotes:

Code:

sed -i "s/$password//" file.lst

but this will not work if $password expands to a string that contains a / or any character that has a special meaning in a basic regular expression (such as ., *, ?, [, \, or {). And, even if that isn't a problem, there is also the chance that the user's selected password will match other text in file.lst (and remove it) even though the text removed was not in the password field. (So, if someone knows what this file is supposed to look like, you could expose that user's password by removing the password.)

Rather than editing this file, it would be safer to just remove it.