Coronna688,
Ouch. Yes, you're correct. In shell's test, [ "$arg" ] tests for non-empty string; not non-zero and non-empty (as in awk).

For clarity when reading a script, I don't usually use:

Code:

if ! tail -50 SapAdapterInboundRfc-P30-SapAdapterInboundSynchronous.log | grep -i "Error" >/dev/null

when the compound-list is more than about 40 characters long, but that is just my personal preference. We don't want the > /dev/null here because this code is replacing earlier code that was:

Code:

returned=`tail -50 SapLogs.log | grep -i "Error"`
echo $returned

and then checking whether "$returned" expands to an empty string.


And, now for the good news...
jedzio,
Know that we know you're using bash on a Linux distro (even though it hasn't been updated for four years), I think I know what the problem is. I should have asked what editor you were using!

To get that error message from bash for the command: set -xv, you must be using an editor that uses the DOS convention of carriage-return followed by newline as the line terminator instead of the UNIX/Linux convention using only the newline.

So, I think you can get your script to work if you write this into a new file (let's call it newscript):

Code:

#!/bin/bash
echo "=== Checking logs ==="
tail -50 SapAdapterInboundRfc-P30-SapAdapterInboundSynchronous.log | grep -i "Error"
if [ $? -ne 0 ]; then
    echo "There is no error in the last 50 lines in the logfile"
fi
echo "=== Last log entry ==="
var=$(tail -1 SapAdapterInboundRfc-P30-SapAdapterInboundSynchronous.log | awk '{print substr($0,13,8)}')
echo "Time elapsed since last entry =" $(( $((`date +%s -d $var`)) - $((`date +%s`)) ))

and then run the commands:

Code:

tr -d '\r' < newscript > checklogs.sh
chmod +x checklogs.sh

to remove any extraneous carriage return characters in your script and make it executable again.

Let us know what happens.

We usually only see this problem on files that have been copied from Windows systems to UNIX and Linux systems. I strongly suggest that you look at the documentation for your editor to see if there is a way to set the characters used as line terminators. If there isn't any way to set the line terminator to just a newline (AKA linefeed) character, seriously consider learning how to use vi or emacs instead of your current editor. Extraneous carriage returns in shell scripts, source code for other languages, and in data files will cause you no end of grief.