[SOLVED] Capture output of a multiline ssh command

Issue

I want to count the number of files of a given type on a remote server. For that I need to ssh and run the commands to count the files on the remote server and then somehow return that value. I thought about just printing the value and trying to capture that output

What I have so far is:

START=0
LAST=5
ssh -i $KEY $USERNAME@$HOST << EOF

  N_FILES=0;
  for (( d=$START; d<=$LAST; d++ ))
  do
        check_day=`date +"%Y-%m-%d" -d "$d day ago"`

        FILES_FOUND="\$(find &DIR | grep $check_day | wc -l)"

        N_FILES=\$(( \$N_FILES + \$FILES_FOUND ))

  done
  echo $N_FILES

EOF
N_FILES=$?

The above code runs fine but yields 0, when there are actually files found in the server co capturing the output this way is not working. Can somebody help here please?

Solution

You could simply assign the result of the SSH command to a variable:

IFS="" N_FILES=$(ssh -Ti $KEY $USERNAME@$HOST << EOF

  N_FILES=0;
  for (( d=$START; d<=$LAST; d++ ))
  do
        check_day=`date +"%Y-%m-%d" -d "$d day ago"`

        FILES_FOUND="\$(find &DIR | grep $check_day | wc -l)"

        N_FILES=\$(( \$N_FILES + \$FILES_FOUND ))

  done
  echo $N_FILES

EOF
)
echo $N_FILES

Note: the N_FILES before ssh is not the same N_FILES used inside the ssh command.
But its value (provided none of the other ssh commands have any output) will be the same.

The -T seems important here: no need to request a pseudo-TTY to assign the output to a variable.

Answered By - VonC

Answer Checked By - Senaida (WPSolving Volunteer)