bash if-statement issues

[aliaseer]

I'm having trouble with the following line:

if [ "$verbose" -eq "$TRUE" ] ; then ...

It gives me

line 22: [: : integer expression expected

but still displays the results I need.

Here's a sample of the output:

[~/Research/hiv/boronated-inhibitors/docked-top-poses] $ m2dc
~/scripts/m2dc: line 22: [: : integer expression expected
3.89480383844937690078
~/scripts/m2dc: line 22: [: : integer expression expected
3.94594374389701607666

Here's the full source:

#!/bin/bash

let TRUE=0
let FALSE=1

if [ "$1" == "-v" ] ;  then
	verbose=0
fi

let counter=0
for file in `ls -1 *.mol2` ; do
	array[$counter]=$file
	let counter=$counter+1
done

let n=0
for (( i=0; i<$counter; i++ )) ; do
	for (( j=$i+1; j<$counter; j++ )) ; do
		let n=$n+1
		distance=$(vd $(m2distances ${array[$i]}) $(m2distances ${array[$j]}))
		
		if [ "$verbose" -eq "$TRUE" ] ; then
			echo "$n: Comparing: ${array[$i]}: to: ${array[$j]}: $distance" > /dev/stdout
		else echo $distance > /dev/stdout
		fi
	done
done

echo
echo "$n comparisons done."

The "vd", and "m2distances" are scripts that I wrote while fiddling around with awk. vd finds the distance between two points in 3d space and m2 distances uses awk to extract their coordinates out of a .mol2 file.

I'm pretty new to scripting, so any help/ideas/tips would be appreciated.
Thanks.

[Franklin52]

The reason for the error is that if $1 is not "-v" the variable $verbose is not set, replace this:

if [ "$1" == "-v" ] ;  then
	verbose=0
fi

with:

if [ "$1" == "-v" ] ;  then
	verbose=0
else
	verbose=1
fi

Regards

[drl]

Hi.

Does this example help you?

#!/bin/bash

# @(#) s1       Demonstrate useful debugging technique.

echo
echo "GNU bash $BASH_VERSION" >&2

# Define function to test value of variable "verbose".

check() {
  if [ "$verbose" -eq "$TRUE" ]
  then
    echo " verbose was true."
  elif [ "$verbose" -eq "$FALSE" ]
  then
    echo " verbose was false."
  else
    echo " verbose set to unknown value."
  fi
}

let TRUE=0
let FALSE=1

verbose="$TRUE"

echo
echo " First invocation:"
check

unset verbose

echo
echo " Second invocation:"
check

set -o nounset

echo
echo " Third invocation:"
check

exit 0

producing:

% ./s1

GNU bash 2.05b.0(1)-release

 First invocation:
 verbose was true.

 Second invocation:
./s1: line 11: [: : integer expression expected
./s1: line 14: [: : integer expression expected
 verbose set to unknown value.

 Third invocation:
./s1: line 11: verbose: unbound variable

cheers, drl

[aliaseer]

if [ "$1" == "-v" ] ;  then
	verbose=0
else
	verbose=1
fi

Excellent, that fixed the problem. Thank you.

@drl:
Yes, thanks. The example is quite helpful: I'll be taking another look at I/O redirection and I've never seen the "set" builtin before so I'll be watching for that too.