Ubuntu – How to read a variable from a file

AWK can search and replace text as well, so there is no need to use grep or sed. The code bellow extracts substring from second column (webN), increments N, and substitutes second field with webN+1

$ cat testInput.txt                                                                                          
project web0
other
project web1
$ awk '/web/{ num=substr($2,4)+1;$2="web"num };1' testInput.txt                                              
project web1
other
project web2

This will print edited file on screen. You can save that to another file like so awk [rest of code here] > fileName.txt and replace original with new using mv fileName.txt oldFile.txt

The main problem is here:

read $input

In bash, usually, $foo is the value of the variable foo. Here, you don't want the value, but the name of the variable, so it should be just:

read input

Similarly, in the if tests, $yes and $no should be just yes and no, since you just want the strings yes and no there.

You could use a case statement here, which (IMHO) makes it easier to do multiple cases based on input:

case $input in
[Yy]es)    # The first character can be Y or y, so both Yes and yes work
    echo "Hello!"  
    echo "Hello!" | festival --tts
    ;;
[Nn]o)     # no or No
    echo "Are you sure?"
    echo "Are you sure?" | festival --tts
    ;;
*)         # Anything else
    echo "Please answer yes or no."
    echo "Please answer yes or no." | festival --tts
    ;;
esac

You could wrap the two echo statements and the use of festival in a function to avoid repeating yourself:

textAndSpeech ()
{
    echo "$@"
    echo "$@" | festival --tts
}
case $input in
[Yy]es)    # The first character can be Y or y, so both Yes and yes work
    textAndSpeech "Hello!"  
    ;;
[Nn]o)     # no or No
    textAndSpeech "Are you sure?"
    ;;
*)         # Anything else
    textAndSpeech "Please answer yes or no."
    ;;
esac

With $input, bash replaces this with its value, which is nothing initially, so the read command run is:

read 

And read by default stores the input in the variable REPLY. So you can, if you want, eliminate the input variable altogether and use $REPLY instead of $input.

Also have a look at the select statement in Bash.