Question

I am trying to compare two text in Unix. I tried the below. It didn’t work. In need to compare the first and last lines of a file.

firstline=`head -1 test.txt`
echo $firstline
lastline=`tail -1 test.txt`
echo $lastline
if [ $firstline == $lastline ]
then
   echo "Found"
fi

Surely, am missing something. Please help.

Answer 1

Perhaps simpler…

bash-3.2$ if [ "$(sed -n '1p' file)" = "$(sed -n '$p' file)" ]; then
    echo 'First and last lines are the same'
else
    echo 'First and last lines differ'
fi

---

Update to answer Jan’s questions.

bash-3.2$ cat file
-z
-G
bash-3.2$ if [ "$(sed -n '1p' file)" = "$(sed -n '$p' file)" ]; then
>     echo 'First and last lines are the same'
> else
>     echo 'First and last lines differ'
> fi
First and last lines differ

I prefer sed for grabbing the first and last lines of a file because the same command-line works on Linux, Mac OS and Solaris. The head and tail command-lines are different between Linux and Solaris.