Verifying that a copy succeeded

Question

I would like to write a script that verifies if a copy succeeded or not. Here's what I have:

#!/bin/sh
cp home/testing/present.txt home/testing/future.txt
   echo "Copy Code: $? - Successful"
if [ $? != 0 ]; then
   echo "Copy Code: $? - Unsuccessful"
fi

The "if" statement is not being initialized. How can resolve this? Thank You for your time.

Answer 1

$? refers to the last command:

#!/bin/sh
cp home/testing/present.txt home/testing/future.txt
   echo "Copy Code: $? - Successful"   # last command: cp
if [ $? != 0 ]; then                   # last command: echo
   echo "Copy Code: $? - Unsuccessful" # last command: [
fi

If you want to repeatedly work with the status of a specific command, just save the result in another variable:

#!/bin/sh
cp home/testing/present.txt home/testing/future.txt
status=$?
echo "Copy Code: $status - Successful"
if [ $status != 0 ]; then
   echo "Copy Code: $status - Unsuccessful"
fi

However, a better approach is to simply test the cp command in the first place:

if cp home/testing/present.txt home/testing/future.txt
then
  echo "Success"
else
  echo "Failure, exit status $?"
fi