Syntax error: invalid token operator (error token is "

Question

Doing a basic shell script I'm having trouble with getting the length of a file with curl and later dividing it, and the text:

syntax error: invalid token operator (error token is"

keeps appearing.

Simplified code would be:

    head=$(curl -sI $dir | awk '/Content-Lenth/{print $2}') 
    res=$(($head/3))

I've been reading solutions to similar problems and they said removing the \r that the variable is probably having at its end, so I put this in the middle of the two lines, but the problem is still there:

head=${head//\r}

Any idea why this happens? Is it because of an \r character at the end? If it's the case, how to remove it?

Sounds vaguely like [Difference between sh and bash](https://stackoverflow.com/questions/5725296/difference-between-sh-and-bash); how exactly are you running this script? A DOS carriage return in your data could not produce a syntax error in your script (but you want `$'\r'` instead of just `\r`). — tripleee, Apr 27 '21 at 18:02
@Barmar /3")syntax error: invalid arithmetic operator (error token is " — Carlos González-Almansa Laredo, Apr 27 '21 at 18:15
Maybe you ough to temporarily add `echo "$head"` after the first line so you can see what that variable actually contains. — , Apr 27 '21 at 18:20
@Roadowl I've been doing that, and it is a number but with a new line character because if i put some text after it appears in a new line, but i'm having difficulties to get rid of it. — Carlos González-Almansa Laredo, Apr 27 '21 at 18:26

score 0 · Answer 1 · answered Apr 27 '21 at 19:40

I was able to reproduce your issue, which for me was indeed caused by a carriage return at the end of the value of $head. That arises from the HTTP protocol specification: HTTP uses carriage return / newline sequences as line terminators (like DOS and Windows), and awk will not recognize the carriage return as whitespace.

Your attempt to remove the carriage return ...

head=${head//\r}

... does not serve that purpose. The \ is a general escape character to the shell, preserving the literal meaning of whatever character follows. Since the character r has no special significance to the shell, the above code is equivalent to

# Oops, not what you meant:
head=${head//r}

I used this alternative:

# Strip all non-digits:
head=${head//[^0-9]}

, and that resolved the issue for me.

Do also note, however, that

you have misspelled "Length", and
HTTP header names are not case sensitive, but by default, awk regular expressions are. Therefore, your awk command might in some cases fail to match the wanted header even after the spelling is corrected.

Here's a version of your script that addresses all of these issues:

head=$(curl -sI "$dir" | awk 'BEGIN{IGNORECASE=1} /Content-Length/{print $2}') 
head=${head//[^0-9]}
res=$(($head/3))

The last two lines could be merged into one, but I have kept them separate for clarity. That might also serve well if you want to use the value of $head for other purposes, too.

See https://stackoverflow.com/questions/15520339/how-to-remove-carriage-return-from-a-variable-in-shell-script for how to remove CR from a variable. — Barmar, Apr 27 '21 at 19:43

Syntax error: invalid token operator (error token is "

1 Answers1