Week 8, Intro to Unix lab 2016

Content

• Your job is to submitt correct solutions which work both on lab machine e.g u-pl24 and solaris u-us. If they won’t pass automatic test, 0 points will be rewarded!
  • It includes proper email subject and proper file naming
  • I will be sending back error messages
  • How to verify it on both: If you hate it, automate it.
• Recap homework
  • sed -i not standard but useful
  • sed -e useful to use explicitly. Be careful of ordering of options especially -n
  • sed 1~2d is not standard. You can check http://pubs.opengroup.org/onlinepubs/9699919799/ after searching sed
  • functions are very useful but not standard
  • bashism
    • $(( 1 +2 ))
    • ((k++))
  • while cond ; do command ; done - no ; after do
  • while read x ; do echo $x ; done - how to detect end of file
  • escaping variables "$i"
  • indent in last homework
    • printf for find is not in standard
• Recap test and Bonus from previous week
  • Solution where "he said she said: \"unix rocks\"" can be passed as arguments
• Print lines 7-9 using sed from seq 10000. Measure time. What is the fastest solutions?
• processes: fg, bf, Ctrl-C, Ctrl-Z, Ctrl-Y, jobs
  • Bash and catching signals

Homework

I am sorry for my delay I was ill.

The deadline will be till next week May 5th 2016, 23:59.

Note that the scripts works on Solaris and Gentoo in MS Rotunda laboratory, so keep it that way. It will be evaluated on machine u-pl2[0-9] and u-ss.

• (1 point) Understand and modify a script ifs.sh so it prints a template only for users whose login is a substring of their name.
  • See one line from many which match the criteria:
    • Uzivatel 'vyuka laborator' ma login 'vyuka' and uid (50000).
    • Understand what is a template and what are the variables which should differ for each line
    • Note that login vyuka is substring from users name vyuka laborator.
  • Send me
    • ifs_${YOUR_NICKNAME}.sh modified script
    • ifs_${YOUR_NICKNAME}.output the scripts output
• (1 point) Understand and modify a script args.sh so it prints every second word (argument) from this single command set -- /usr/*
  • Send me - both args_${YOUR_NICKNAME}.sh and args_${YOUR_NICKNAME}.output
• (1 point) Understand and modify a script kill.sh so produces these two desired lines into file kill.out.
  • Send me only the modified script named kill_${YOUR_NICKNAME}.sh, but modify only the three lines marked for modification.
  • See kill man page before running the script.
  • Follow the instructions in the kill.sh script and investigate its behaviour.
  • Desired output stored in file kill.out with two lines:

You should run this script and press Ctrl+C to see me
Runn kill and my PID. That should be enough

HW Solutions

• kill_solution.sh
• week08_args.sh