Homework of week 6 (Submission deadline: 23:59, Oct. 14, 2025)

1. Write a shell script to do statistics for the user login time at Ukko during Sep. 01 - Oct. 19, 2022, according to the file ~jsyu/202209-10.log at Ukko (md5sum of this log file is: 29db07be08d403cc8d2127151b88299e). The format of login time inside the parentheses is (dd+hh:mm).
   Also sort the final statistics according to decresing login time, in the aligned format of, for example:

   
   jsyu       22 Days 22 Hours 22 Minutes
   u0317011   11 Days 11 Hours  1 Minutes
   u123456789 10 Days  2 Hours 20 Minutes
   ......
   
   

   
   
2. According to the table of atoms,
   1. Write a script to sort the table according to the atomic number (in the order of increasing), and write it to another HTML table that only contains three columns of data, in terms of atomic number, atom symbol and atomic mass.
   2. Try to find out the elements whose atomic masses do not increase with the atomic numbers, and report them in neighboring pairs. You only need to report those elements with atomic numbers ≤ 100.
      You can check your answer against the periodic table at Wiki.
      sdiff <(awk -F' ' '{print $2, $3, $4}' ~jsyu/atom-list.txt |sed -e 's/(//g' -e 's/)//g' | sort -k 2 -g) <(awk -F' ' '{print $2, $3, $4}' ~jsyu/atom-list.txt |sed -e 's/(//g' -e 's/)//g' | sort -k 3 -g)
      
      
   
   
   
3. Watch the MV.
   
   

for i in `cat /etc/passwd | cut -d : -f 1`
   do echo $i ;
   finger $i ;
done

for i in $(cat /etc/passwd | cut -d : -f 1)
   do echo $i ;
   finger $i ;
done

head /etc/passwd                  #Get the first 10 lines by default
head -20 /etc/passwd              #Get the first 20 lines of /etc/passwd 
tail /etc/passwd                  #Get the final 10 lines by default    
tail -20 /etc/passwd              #Get the final 20 lines of /etc/passwd 
head -20 /etc/passwd | tail -2    #Get the 19th and 20th lines of /etc/passwd
head -20 /etc/passwd | tail -1    #Get the 20th line of /etc/passwd