[Techtalk] problem with changing directory in a script

[Miriam English]

Thanks James. Now I understand.

I actually wanted this for a script I was writing. The script needs to 
be able to check paths to some files, so I keep these paths in a file, 
then read each path in, one at a time, for the program to use. Some of 
the paths point to subdirectories of the home directory, which I had 
hoped to name using the tilde to make it general-purpose instead of 
hard-coding it for me. This was the stumbling block. When reading them 
from the file bash doesn't expand them and they give a "not found" error.

It looks like there isn't any way to use the tilde, then... unless I 
write my own expansion routine... which is too much hassle as this is 
just a crappy program for my own use. I was just wanting to make it more 
general-purpose in case it might be useful for other people.

No matter. Thanks for the help. :)


On 14/09/15 19:13, James Sutherland wrote:
> On 14/09/2015 10:03, Miriam English wrote:
>
>> Does anybody know why the tilde appears to trip this up?
>> And if there is a workaround?
>
> The problem is that the tilde isn't really part of the directory name.
> It's a handy shortcut for "my home directory", which bash normally
> expands for you to something like /home/miriam before using. In this
> case, the problem is the use of quotes around the value, which stops
> bash making that change:
>
> james at us:~$ echo ~
> /home/james
> james at us:~$ echo "~"
> ~
> james at us:~$ export test=~ ; echo $test
> /home/james
> james at us:~$ export test="~" ; echo $test
> ~
>
> If I enter a command of "cd ~", I will be in my own home directory. Put
> quotes around the ~, I will be told there is no directory called ~.
>
>
> James.
>
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