Using "while read" causes ambiguous redirect-CodePudding

i have this very simple script:

data=$(<data.txt)
counter=10

#just a dbquery using $data
result=(`psql -X -t -AF $'\t' -h $POSTGRES_HOST -d $POSTGRES_DATABASE -U $POSTGRES_USERNAME  -w -c "select COUNT(field_value) from table where field_value in ($data)"`)

if [ $result == counter ]; then
    echo -e "\e[92m Success \e[39m"
  else
    while read -r dataLine;
      do
        result=(`psql -X -t -AF $'\t' -h $POSTGRES_HOST -d $POSTGRES_DATABASE -U $POSTGRES_USERNAME  -w -c "select field_value from fields where field_value = $dataLine" `)
        if [ -z "$result" ]; then
          echo "$dataLine failed"
        fi
      done < $data
fi

I am getting line 17: $data: ambiguous redirect (where fi is) i imagine the issue is something with the first line reading data.txt then later referencing $data on the read -r but im not exactly sure what is wrong.

Any ideas?

edit: error in line 17, not 21.

edit2: fixed "results" typo inside the loop.

edit3: data.txt contains a list of UUIDs:

'5dce6dcc-5368-4dc2-b26e-01b92c3dd3aa',
'6dab9b13-1734-4766-93f5-a96d0e0afd38',
'c365e709-296b-4e8e-acf9-1d9e252325f6'

CodePudding user response：

The < redirection takes a filename, but you are passing it string data.

To redirect from a string, use a <<< here-string instead:

data=$(< data.txt)
cat <<< "$data"

Or if you are using sh instead of bash, use a short here-doc:

cat << end
$data
end

Though it would be better to just read directly from the file, since this allows you to stream arbitrary amounts of data without reading it into memory first:

data="data.txt"
cat < "$data"

While not applicable to this question, but for the benefit of future readers, you also get this error if you try to redirect from a file with spaces in the name:

$ file="my file.txt"
$ cat < $file
bash: $file: ambiguous redirect

In this case you simply have to quote the variable:

$ cat < "$file"
My file contents