Passing commands to Functions in BASH

[iMetaphysikz]

#!/bin/bash

ask()
{
$1
}

ask "echo This is not working >> 2.txt"

Can anyone enlighten me on this one?
The echo command works but the re-direction to the text file 2.txt does not work
Can someone explain why this is the case.

[TeoBigusGeekus]

Try with this

#!/bin/bash

ask()
{
$1
}

ask "echo This is not working" >> 2.txt

[Thorsen V]

try:

ask()
{
$1
}

ask "echo This is not working" >> 2.txt

ETA: TeoBigusGeekus, you beat me by a minute

[scheibenlosen]

#!/bin/bash

ask()
{
$1
}

ask "echo This is not working >> 2.txt"

Can anyone enlighten me on this one?
The echo command works but the re-direction to the text file 2.txt does not work
Can someone explain why this is the case.

Try removing ask(), and then as a command, sh ask "echo This is not working" >> 2.txt It works for me.

[sudodus]

What do you want to do? Maybe you can use the read command of bash to assign your input to a variable. Test making the file echoer of the following three lines

#! /bin/bash

echo "Input line of text and press Enter"
read txt
echo "Echoing $txt"

and run it with

bash ./echoer

[iMetaphysikz]

The Problem that i now have is that if i want a second command/line of text that I want to pass to the function for example "echo hello" redirects its output to the 2.txt file as-well

This is

#!/bin/bash

ask()
{
$1
$2
}

ask "echo This is not working" > 2.txt "echo hello"

[Thorsen V]

that works how I'd expect it to.

Can you clarify what you're trying to so?

[Thorsen V]

#!/bin/bash

ask()
{
$2 > $1
$3
}

ask "2.txt" "echo This is not working" "echo hello"

This prints "This is not working" to file and hello to the console ... is that what you're after?

[Khayyam]

iMetaphyisicz ...

I think you are 're-using' my function without understanding 'function' and its use.

#!/bin/bash

function ask()
{   
    echo -n "$@" '[y/n] ' ; read ans
    case "$ans" in
        y*|Y*) return 0 ;;
        *) return 1 ;;
    esac
}

ask "Do you understand functions?" &&
echo "YES" > yesweunderstandfunctions.txt

In your example the "function" is whatever is passed as parameter "${1}" to the script.

% cat param.sh
#!/bin/bash

echo "Parameter \${1} is ${1}"
% param.sh yes
Parameter ${1} is yes
% param.sh gobbldygook
Parameter ${1} is gobbldygook

Not the best way to provide a function ... it might help if you explain what your trying to do. The following perhaps?

#!/bin/bash

if [[ -z ${@} ]]; then
    echo "No question provided."
    echo "Usage: $(basename ${0}) question"
    exit
fi

function ask()
{   
    echo -n "$@" '[y/n] ' ; read ans
    case "$ans" in
        y*|Y*) return 0 ;;
        *) return 1 ;;
    esac
}

ask "${@}" && echo "${@}=YES" > answer.txt

Just so you understand, functions can do other things other than 'ask' questions.

nd () {
  test -d "${1}" || mkdir -p "${1}" && cd "${1}"
}

With this function 'nd newdir' will make a directory 'newdir' and 'cd newdir'.

Hope that helps clarify things ... khay

[iMetaphysikz]

Thanks Khayyam.

Essentially I am trying to reuse the ask function to do different things depending on the situation, in some instances I want to append to a log file, in other instances I want to call another function depending on user response.

In the code below rdx would be another function that the script calls

ask()
{
        local  i=0

        for i in {1..10}
                do

                        echo -n "$1"
                        read ans
                        ans=$(echo $ans | tr '[A-Z]' '[a-z]')

                        case $ans in
                                y)
                                        $2
                                        return 0 ;;
                                n)
                                        $3
                                        return 0 ;;
                                *)
                                        echo  "Please enter y or n"
                                        local j=$((10-$i))
                                        echo  "If neither y/n is pressed after $j attempts it will be assumed that $3"
                        esac

        done
        echo $3
}

ask "Please Enter an RDX Cartridge if formatting is required, is the RDX cartridge inserted (y/n)?" "rdx" "RDX Cartridge formatting is not required"

ask "echo Has this script been useful" "echo Very Useful >> feedback.txt" "echo Try again Buddy >> feedback.txt"

Now using your code with the && will add text to the yesweunderstandfunctions.txt if the user says yes because the function was successfully completed, but if the user says no it will not, I would also have to capture this information to a text file.

That's why I have used the "echo Very Useful >> feedback.txt"

ask "Do you understand functions?" &&
echo "YES" > yesweunderstandfunctions.txt

Note, the code I have written above may not work as it was a rough example, as I ammended it from the script I'm currently writting. However I do not have that script on the computer I'm currently on.