Impossible bash: syntax error: invalid arithmetic operator (error token is "")

Question

I know there have been a lot of similar questions here but this is pretty special, please read on.

I have a bash script that does nothing but comparing two numbers, basically like that:

[[ 1408039118 -lt 1401215749 ]]

Now, running that script throws the following error:

/usr/bin/pacaur: line 179: 1408039118: syntax error: invalid arithmetic operator (error token is "")

So I understand something must be wrong, this is my line 179:

[[ "${depsAlastmodified[$i]}" -lt 1401215749 ]] && note "f" $"no AUR metadata for ${colorR}${depsAname[$i]}${reset} package"

Running this through bash -x shows:

+ [[ 1408039118 -lt 1401215749 ]]
/usr/bin/pacaur: line 179: 1406628774: syntax error: invalid arithmetic operator (error token is "")

There is really nothing visible wrong with that. I tried some further debugging using od -c on that variable:

echo ${depsAlastmodified[$i]} | od -c

The output is:

+ echo '1408039118'
+ od -c
0000000   1   4   0   8   0   3   9   1   1   8 033   [   m 033   [   K
0000020  \n
0000021

But now I'm not sure how to read this. I understand the newline character is belonging to the echo command. But what is 033 [ m 033 [ K exactly? And does this belong to my issue?

I also tried running that number through bc:

echo ${depsAlastmodified[$i]} | bc | od -c

This is the output:

+ echo '1408039118'
+ bc
+ od -c
(standard_in) 1: illegal character: ^[
(standard_in) 1: syntax error
(standard_in) 1: illegal character: ^[
(standard_in) 1: illegal character: K
0000000

Something is wrong with that variable. What else could I try? How to fix this?

Just for reference, this is the full issue history.

Answer 1

Looks like you have trailing characters in your array.

Try this with tr -cd '[[:digit:]]' which will delete all non digits from input:

echo "${depsAlastmodified[$i]}" | tr -cd '[[:digit:]]' | od -c

It should give:

0000000   1   4   0   8   0   3   9   1   1   8
0000012