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i need diff understanding :)

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Top Forums Shell Programming and Scripting i need diff understanding :)
# 1  
Old 09-30-2009
i need diff understanding :)
Can someone tell me where i'm going wrong

Code:
if [ "$file1" \< "$file2" ]; then                 
     set outPut = diff "$file1" "$file2" | wc -l
     echo $file1 $file2;
     echo "$outPut"
        if [$outPut == 0];then
                echo " "$file1" and "$file2" " v
         fi
fi

This is the following result:

Quote:
./Assgn1.bash: line 52: [: missing `]'
0
file txt.txt~

./Assgn1.bash: line 52: [: missing `]'
./Assgn1.bash: line 40: [: too many arguments
0
txt txt.txt

line 52 is referring to the "if [$output = 0]; then"
and line 40 refers "if [ ! -f $file2 ]; then" which is not listed.
# 2  
Old 09-30-2009
It's missing spaces after [, before ]



Code:
if [ "$file1" \< "$file2" ]; then                 
     set outPut = diff "$file1" "$file2" | wc -l
     echo $file1 $file2;
     echo "$outPut"
        if [ $outPut == 0 ];then
                echo "$file1 and $file2" v
         fi
fi



I don't really know what \< means!
# 3  
Old 10-01-2009
i've checked all the white spaces but I still can't see where else the problem is this what i have now

Code:
                if [ ! -f $file1 ]; then
                   continue
                   fi
                for file2 in *
                  do
                  if [ ! -f $file2 ]; then
                     continue
                     fi

		#//checks if file1 is being compared to another different file; not itself
                if [ "$file1" \< "$file2" ]; then 
                     set outPut = `diff "$file1" "$file2" | wc -l`
                     if [ $outPut == 0 ]; then
                         echo " "$file1" and "$file2" " # // prints file if same content
                     fi
                fi

Again the error message is

Quote:

line 62: [: ==: unary operator expected
./forYourEyesOnly.bash: line 50: [: untitled: binary operator expected
./forYourEyesOnly.bash: line 55: [: untitled: binary operator expected
62: refers to if [ $outPut == 0 ]; then
50. refers to if [ ! -f $file1 ]; then
55. refers to if [ ! -f $file2 ]; then

White spaces again?
# 4  
Old 10-01-2009
I've never heard of the '\<' operator before (line 60 by your reckoning). Could you explain that one?
# 5  
Old 10-01-2009
For line 62 it might be that one of the files does not exist, or that one of the variables $file1 or $file2 are not declared (I can't see where $file1 is declared in your script).

Use
Code:
outPut = $(diff $file1 $file2 2>/dev/null | wc -l)
if [ $outPut == 0 ]; then
...

or better
Code:
diff $file1 $file2 > /dev/null 2>&1
if [ $? -eq 0 ]; then
...

And it pointless to say
Code:
for file2 in *
do
 if [ ! -f $file2 ]; then
   continue
 fi
...

because if * expands nothing the for-loop is not executed, so you can assume that file2 does exist.

And use "set -n" in your script (ksh - or the equivalent for your shell) to check the syntax without running it to see where the errors are.

(oh, and what is the \< all about?)
# 6  
Old 10-01-2009
Quote:
Originally Posted by taiL
i've checked all the white spaces but I still can't see where else the problem is this what i have now

Code:
                if [ ! -f $file1 ]; then
                   continue
                   fi
                for file2 in *
                  do
                  if [ ! -f $file2 ]; then
                     continue
                     fi

        #//checks if file1 is being compared to another different file; not itself
                if [ "$file1" \< "$file2" ]; then 
                     set outPut = `diff "$file1" "$file2" | wc -l`
                     if [ $outPut == 0 ]; then
                         echo " "$file1" and "$file2" " # // prints file if same content
                     fi
                fi

Again the error message is



62: refers to if [ $outPut == 0 ]; then
50. refers to if [ ! -f $file1 ]; then
55. refers to if [ ! -f $file2 ]; then

White spaces again?
Umm, I have never heard of '<' operator for test command, test being synonym for '['. If you (according to your comment in the code) want to check that you are not comparing a file against itself, use -ef operator of test.

Furthermore, there is no such operator as '==' - if you want to compare numbers, use -eq, for strings the comparison operator is '='.

Regards,

pen
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