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Shell script for comparing certain lines in two files

I spent 3 days in searching and trying different scripts and packages but i have no success. All I want to do is compare first and last 2 lines in 2 files.

10x to all.

Code:

#!/bin/sh



# change this to the correct 2 files.

FILE_ONE=/path/to/file1

FILE_TWO=/path/to/file2



FILE_ONE_TAIL=`tail -2 $FILE_ONE`

FILE_TWO_TAIL=`tail -2 $FILE_TWO`



if [ "$FILE_ONE_TAIL" = "$FILE_TWO_TAIL" ]; then

    echo The last two lines of the files match.

else

    echo The last two lines of the files DO NOT match.

fi

forrestt already posted, but here's another suggestion:

Code:

#!/bin/sh

echo "First two lines of files:" > temp

head -n 2 file1 file2 >> temp

echo "Last two lines of files:" >> temp

tail -n 2 file1 file2 >> temp

cat temp

Here is a slightly more robust version. This is not guaranteed by any stretch of the imagination because this isn't tested and I'm not a BASH expert.

Code:

#!/bin/sh



## Usage scipt_name.sh <file 1> <file 2>



## file names

FILE_1="$1"

FILE_2="$2"



## if both files exist and are readable

if [ (-r $FILE_1) -a (-r $FILE_2) ]; then



        ## Grab last two lines of each file

        FILE_1_END="`tail -2 $FILE_1`"

        FILE_2_END="`tail -2 $FILE_2`"



        ## Compare last two lines

        if [ "$FILE_1_END" == "$FILE_2_END" ]; then

            echo "The last two lines of the files match.\n"

        else

            echo "The last two lines of the files DO NOT match.\n"

            echo "The last two lines of the first file are:\n $FILE_1_END\n"

            echo "The last two lines of the second file are:\n $FILE_2_END\n"

        fi





        ## Grab last two lines of each file

        FILE_1_START="`head -n 2 $FILE_1`"

        FILE_2_START="`head -n 2 $FILE_2`"



        ## Compare first two lines

        if [ "$FILE_1_START" == "$FILE_2_START" ]; then

            echo "The last two lines of the files match.\n"

        else

            echo "The first two lines of the files DO NOT match.\n"

            echo "The first two lines of the first file are:\n $FILE_1_START\n"

            echo "The first two lines of the second file are:\n $FILE_2_START\n"

        fi

else

        echo "Either the files don't exist or you don't have permission to read them.\n"

fi

You can't have spaces in a variable assignment in bash. But I agree, your program is more robust. Change the lines:

Code:

FILE_1 = "$1"

FILE_2 = "$2"

Code:

FILE_1="$1"

FILE_2="$2"

Quote:

Originally Posted by forrestt

You can't have spaces in a variable assignment in bash. But I agree, your program is more robust. Change the lines:

Code:

FILE_1 = "$1"

FILE_2 = "$2"

Code:

FILE_1="$1"

FILE_2="$2"

Thanks for the input. I've made the requested changes. I can't test because I'm on a *gulp* Windows 2000 PC *gulp* at work.

Thanks again!

Well, it isn't working anyway (several other minor errors). I'm fixing it and will post results shortly.

Code:

#!/bin/sh



## Usage scipt_name.sh <file 1> <file 2>



## file names

FILE_1="$1"

FILE_2="$2"



echo $FILE_1 $FILE_2

## if both files exist and are readable

if [ -r "$FILE_1" ]; then

  if [ -r "$FILE_2" ]; then



        ## Grab last two lines of each file

        FILE_1_END=`tail -2 $FILE_1`

        FILE_2_END=`tail -2 $FILE_2`



        ## Compare last two lines

        if [ "$FILE_1_END" = "$FILE_2_END" ]; then

            echo "The last two lines of the files match.\n"

        else

            echo "The last two lines of the files DO NOT match.\n"

            echo "The last two lines of the first file are:\n$FILE_1_END\n"

            echo "The last two lines of the second file are:\n$FILE_2_END\n"

        fi





        ## Grab first two lines of each file

        FILE_1_START=`head -2 $FILE_1`

        FILE_2_START=`head -2 $FILE_2`



        ## Compare first two lines

        if [ "$FILE_1_START" = "$FILE_2_START" ]; then

            echo "The first two lines of the files match.\n"

        else

            echo "The first two lines of the files DO NOT match.\n"

            echo "The first two lines of the first file are:\n$FILE_1_START\n"

            echo "The first two lines of the second file are:\n$FILE_2_START\n"

        fi

    else

        echo "Cannot read $FILE_2"

    fi

else

    echo "Cannot read $FILE_1"

fi

Quote:

Originally Posted by forrestt

Well, it isn't working anyway (several other minor errors). I'm fixing it and will post results shortly.

Thanks for taking a look at it. I've made a couple modifications since your post to fix the extremely noticable errors. That's what I get for writing it fast.

Centinul

I just have the advantage of being able to debug it :)