bash string compare

Question

I'd like to compare an Output with an string. My script looks like this:

#!/bin/bash
DRBD=$(drbd-overview)
COMP=' 0:nfs-ha/0  Connected Secondary/Primary UpToDate/UpToDate'

DEBUG=1

if [ $DEBUG == "1" ];
then
  echo "Debug:"
  echo $COMP
  echo $DRBD
  echo "Debug-Ende"
fi

if [[ "x$DRBD" = "x$COMP" ]];
then
  RTRN='Check_OK'
else
  RTRN="$DRBD"
fi

echo "Return: $RTRN"

& bash -x script.sh looks like this:

bash -x scripts.sh
++ drbd-overview
+ DRBD=' 0:nfs-ha/0  Connected Secondary/Primary UpToDate/UpToDate '
+ COMP=' 0:nfs-ha/0  Connected Secondary/Primary UpToDate/UpToDate'
+ DEBUG=1
+ '[' 1 == 1 ']'
+ echo Debug:
Debug:
+ echo 0:nfs-ha/0 Connected Secondary/Primary UpToDate/UpToDate
0:nfs-ha/0 Connected Secondary/Primary UpToDate/UpToDate
+ echo 0:nfs-ha/0 Connected Secondary/Primary UpToDate/UpToDate
0:nfs-ha/0 Connected Secondary/Primary UpToDate/UpToDate
+ echo Debug-Ende
Debug-Ende
+ [[ x 0:nfs-ha/0  Connected Secondary/Primary UpToDate/UpToDate  = \x\ \0\:\n\f\s\-\h\a\/\0\ \ \C\o\n\n\e\c\t\e\d\ \S\e\c\o\n\d\a\r\y\/\P\r\i\m\a\r\y\ \U\p\T\o\D\a\t\e\/\U\p\T\o\D\a\t\e ]]
+ RTRN=' 0:nfs-ha/0  Connected Secondary/Primary UpToDate/UpToDate '
+ echo 'Return:  0:nfs-ha/0  Connected Secondary/Primary UpToDate/UpToDate '
Return:  0:nfs-ha/0  Connected Secondary/Primary UpToDate/UpToDate

what did I do wrong that $COMP is escaped within the bash statement?

Answer 1

The two strings are not identical. $DRBD has a space at the end while $COMP doesn't (you can see this in the trace output). This is why the comparison doesn't set RTRN to Check_OK.