Question

PART 1: Explore commands that compare file contents:

• mkdir ~/mod7
• cd mod7
• cp /etc/passwd passwd.bak
• pr passwd.bak
• pr -n -d passwd.bak
• cp passwd.bak passwd.bak2
• Add a new entry towards the top of the passwd.bak2 file for Albert Morris using vi : amorris:x:29000:0:Albert Morris: /home/amorris: /bin/bash)
• cmp passwd.bak2 passwd.bak
• sort passwd.bak
• more passwd.bak
• sort passwd.bak > passwd.bak3
• sort passwd.bak2 > passwd.bak4
• comm  passwd.bak3 passwd.bak4
• diff  passwd.bak passwd.bak2
• TO HAND IN: Take a screen shot of these commands plus their execution for PART 1.

PART 2:  Experiment with additional commands:

• cut -d: -f1 passwd.bak2
• cat  passwd.bak >> passwd.bak4
• sort passwd.bak4 > passwd.bak5
• uniq passwd.bak5
• head passwd.bak5 | tr '[a-z]' '[A-Z]'
• TO HAND IN: Take a screen shot of these commands plus their execution for PART 2.

PART 3:  Explore grep filter commands in Chapter 10:

• grep  "root" passwd.bak
• grep - e  "root"  -e  "amorris" passwd.bak
• ps -ef | grep "your username"   NOTE: replace "your username" with your actual username on the general
• grep "nobody" passwd.bak5
• grep "^nobody" passwd.bak5
• grep "[n*]obody" passwd.bak5
• grep "bash$" passwd.bak5
• TO HAND IN:  Take a screen shot of these commands plus their execution for PART 3.

PART 4:

Explore sed filter commands in Chapter 10:

• sed  '5q' passwd.bak5
• sed - n '1,5p' passwd.bak5
• sed -n '5,8p' passwd.bak5
• sed -n -e  '5,8p'  -e  '20,24p' passwd.bak5
• sed -n  '$p' passwd.bak5
• sed -e  '/:x:0/w passwd.root.bak' passwd.bak5
• vi myscript.sh    NOTE: Develop your own short script
• sed  '1i\#just a comment\' myscript.sh > myscript2.sh
• sed  's/:/|/g'  passwd.bak5 | head
• ls -al | sed '/^.....w/p'    NOTE: See files with write group permissions
• vi  teledir.txt and add the following text:

charles harris 98310200987

bill Johnson 327-100-2345

robert dylan 9632454090

   john woodcock 2344987665

barry wood 234-908-3456

gordon lightfoot 345-987-4670

• sed 's /\([a-z]*\) *\([a-z]*\)/\2, \1/' teledir.txt | sort
• TO HAND IN:  Take a screen shot of these commands plus their execution for PART 4.

Answer 1

Answer to part 1)

-> mkdir is a command to make directory. ~ means to make directory in the current directory.

-> cp is a command to copy files from one directory to another.

-> pr is a command to make the executable for printing.

-> cmp is a command that compares two files and reports the location wherever difference is found. If the files are identical it simply returns.

-> sort is a command that sorts the files line by line .

-> comm is a command to compare two sorted files.

-> diff is a command that returns the location where the files are not identical.

Answer to part 3)

-> grep is a command line utility that searches for a pattern in the given file.

-> ps is a comamnd that displays the process that are currently running in the system.

-> grep ^nobody means to search for a line that starts with nobody. ^ is a regular expression that asks to search for a line starting with any pattern.