assistance on bash script for copying files - linux

Question

I'm new to linux and to bash programming/scripting as well.
Anyhow, I wanted to make a bash script that will do a few things:
will get input on which files to copy
will get the dest folder
will ask wether to copy or move
will do the desired operation
will ask at the end if to continue for another action or not
Now, as for parts 2,3,5 I'm ok but part 1 is kinda problematic.
So, here is the script and I hope that you could enlighten me on where I am wrong and why :)
#! /bin/bash
#beginning
clear
f=1
Beginning()
{
echo "HELLO $USER , THIS PROGRAM WILL COPY THE FILES YOU WANT TO YOUR DESIRED DESTINATION DIRECTORY"
echo -n "please enter the filname/s you want to copy (up to 6 files at a time): ";
echo
EnteringF
}
EnteringF()
{
echo " filename$f : ";
read cop$f
Confirm
}
Confirm()
{
echo "do you wish to copy another file (y/n)?";
read ans
if [ "$ans" = "y" ] || [ "$ans" = "Y" ]; then
f=$[sum=$f+1]
EnteringF
elif [ "$ans" = "n" ] || [ "$ans" = "N" ]; then
Destination
else
echo " invalid choice please try again "
Confirm
fi
}
Destination()
{
echo -n "now please enter the destination folder:";
read dest;
CopyMove
}
CopyMove()
{
echo -n "Do you want to copy or move the files/s? please enter c/m? ";
read choice;
if [ "$choice" = "c" ] || [ "$choice" = "C" ]; then
cp "$cop$f" "$dest";
echo "copied successfully"
UseAgain
elif [ "$choice" = "m" ] || [ "$choice" = "M" ] ; then
mv [ "$files" + "$f" ] "$dest"
echo "moved successfully"
UseAgain
else
echo " invalid choice please try again ";
CopyMove
fi
}
UseAgain()
{
echo "Do you want to use the program again y/n?";
read confirm
if [ "$confirm" = "y" ] || [ "$confirm" = "Y" ]; then
Beginning
UseAgain
elif [ "$confirm" = "n" ] || [ "$confirm" = "N" ]; then
End
else
echo "invalid choice please try again"; UseAgain
fi
}
End()
{
clear
echo "THANK YOU $USER FOR USING THIS PROGRAM :-)"
}
Beginning
Now my main problem is that no data is recorded to cop variable, and therefore cp has nothing to copy.
Maybe I should use some other loop, but I still don't know how to use the others.

Answer 1

You'd want to use an array. I've rewritten some parts of your code:
#!/bin/bash
clear
f=0
cop=()
abort() {
echo >&2 "Something went wrong ($#)."
echo >&2 "Do you have a banana jammed in the keyboard?"
exit 1
}
Beginning() {
echo "HELLO $USER , THIS PROGRAM WILL COPY THE FILES YOU WANT TO YOUR DESIRED DESTINATION DIRECTORY"
echo "please enter the filename/s you want to copy:"
EnteringF
}
EnteringF() {
local i=$((${#cop[#]}+1))
IFS= read -r -e -p " filename$i: " f || abort "EnteringF"
cop+=( "$f" )
Confirm
}
Confirm() {
local ans
read -e -p "do you wish to copy another file (y/n)? " ans || abort "Confirm"
if [[ "${ans,,}" = y ]]; then
EnteringF
elif [[ "${ans,,}" = "n" ]]; then
Destination
else
echo " invalid choice please try again "
Confirm
fi
}
Destination() {
IFS= read -r -e -p "now please enter the destination folder: " dest || abort "Destination"
CopyMove
}
CopyMove() {
read -r -e -p "Do you want to copy or move the file/s? please enter c/m? " choice || abort "CopyMove"
if [[ "${choice,,}" = c ]]; then
if cp -v -- "${cop[#]}" "$dest"; then
echo "copied successfully"
else
abort "cp"
fi
UseAgain
elif [[ "${choice,,}" = m ]] ; then
if mv -v -- "${cop[#]}" "$dest"; then
echo "moved successfully"
else
abort "mv"
fi
UseAgain
else
echo " invalid choice please try again "
CopyMove
fi
}
UseAgain() {
read -e "Do you want to use the program again y/n? " confirm || abort "UseAgain"
if [[ "${confirm,,}" = y ]]; then
Beginning
UseAgain
elif [[ "${confirm,,}" = "n" ]]; then
End
else
echo "invalid choice please try again";
UseAgain
fi
}
End() {
clear
echo "THANK YOU $USER FOR USING THIS PROGRAM :-)"
}
Beginning
I'm not even sure it works, when I tried to run it I had a black screen with a scary prompt asking me what file I wanted to copy or move. I was expecting a pony or something really cool like a cat playing piano. But no. I didn't know what file I wanted to move, actually. I'm not even sure I wanted to move a file. If I had wanted to move a file, I would have used mv directly. I've used a few bashisms for you to dig.
Regarding your question about the variable cop, I used an array, so all the problems are gone at once!
More importantly, there's a huge design flaw in your program: recursion! it's terrible. You're stacking at each step, never releasing the stack. You should really think your design again! Look: if you call your program lol_pony_cat, and if you type this in a terminal:
yes '42' | ./lol_pony_cat
you'll soon obtain
Segmentation fault
That's because:
We start in Beginning
We go in EnteringF and we're prompt for a file name: we enter 42
We go in Confirm and we're prompt for y/n, but we answer an invalid 42, so
We go in Confirm and we're prompt for y/n, but we answer an invalid 42, so
We go in Confirm and we're prompt for y/n, but we answer an invalid 42, so
We go in Confirm and we're prompt for y/n, but we answer an invalid 42, so
We go in Confirm and we're prompt for y/n, but we answer an invalid 42, so
We go in Confirm and we're prompt for y/n, but we answer an invalid 42, so
We go in Confirm and we're prompt for y/n, but we answer an invalid 42, so
We go in Confirm and we're prompt for y/n, but we answer an invalid 42, so
We go in Confirm and we're prompt for y/n, but we answer an invalid 42, so
We go in Confirm and we're prompt for y/n, but we answer an invalid 42, so
We go in Confirm and we're prompt for y/n, but we answer an invalid 42, so
We go in Confirm and we're prompt for y/n, but we answer an invalid 42, so
We go in Confirm and we're prompt for y/n, but we answer an invalid 42, so
We go in Confirm and we're prompt for y/n, but we answer an invalid 42, so
We go in Confirm and we're prompt for y/n, but we answer an invalid 42, so
We go in Confirm and we're prompt for y/n, but we answer an invalid 42, so
We go in Confirm and we're prompt for y/n, but we answer an invalid 42, so...
like this until we reach a stack overflow.
Good luck.