Useful Unix Commands

1.  To convert dos2unix and unix2dos commands.

dos to unix:
        sed 's/\r$//' dos.txt > unix.txt
unix to dos:
        sed 's/$/\r/' unix.txt > dos.txt

            2. To trim the string at both ends.
                   
                      echo "   abcd    abcd   " | xarge
 
                      Ouput: <No spaces>abcd  abcd<no spaces>

           3.  How to find files having a string from set of files

                        find . -name "*.xml" -exec grep -il "33960750"  {} \;
           4. To show first 10 lines in a file

                        head -10 filename.txt

           5. To show last 10 lines in a file.
                        tail -10 filename.txt
           6. To know differences between two files
                        diff filesname1.txt filename2.txt
           7. To sort a file with eliminating duplicates.
                        sort -u filename.txt
           8. find and printing file names only
                        find . -name "*samp*.txt" -print