CS3423-Assignment 3:Awk Solved

Part A
For this part of the assignment, you will create a single command which will take the contents of a passwd file (usually found in /etc/passwd) and print it in sorted order by the user’s last name (that is, their surname, not their username). Normally, you could solve this with the following options on sort: $ sort -t: -k6 /path/to/passwd

You, however, must solve this problem with the utilities covered in class so far. You may (and should) use sort, but you may not use any of its options (e.g., -k, -t, etc).

Example
Input:

lkj293:x:1539:1543:Albert Einstein:/home/einstein:/bin/bash
kkr590:x:1540:1544:Elvis Presley:/home/presley:/bin/bash
nwk409:x:1541:1545:George Washington:/home/washington:/bin/bash
yaa265:x:1542:1546:Bruce Banner:/home/banner:/bin/bash
yhn211:x:1543:1547:George Harrison:/home/harrison:/bin/bash
lfa806:x:1544:1548:Jane Austen:/home/austen:/bin/bash
ilo709:x:1545:1549:Walt Disney:/home/disney:/bin/bash
rfd576:x:1546:1550:Buzz Aldrin:/home/aldrin:/bin/bash
lko889:x:1547:1551:Marie Curie:/home/curie:/bin/bash
cfq219:x:1548:1552:J.R.R. Tolkien:/home/tolkien:/bin/bash
ncz856:x:1549:1553:Christopher Columbus:/home/columbus:/bin/bash
pql747:x:1550:1554:Julius Caesar:/home/caesar:/bin/bash
Output:

rfd576:x:1546:1550:Buzz Aldrin:/home/aldrin:/bin/bash
lfa806:x:1544:1548:Jane Austen:/home/austen:/bin/bash
yaa265:x:1542:1546:Bruce Banner:/home/banner:/bin/bash
pql747:x:1550:1554:Julius Caesar:/home/caesar:/bin/bash
ncz856:x:1549:1553:Christopher Columbus:/home/columbus:/bin/bash
lko889:x:1547:1551:Marie Curie:/home/curie:/bin/bash
ilo709:x:1545:1549:Walt Disney:/home/disney:/bin/bash
lkj293:x:1539:1543:Albert Einstein:/home/einstein:/bin/bash
yhn211:x:1543:1547:George Harrison:/home/harrison:/bin/bash
kkr590:x:1540:1544:Elvis Presley:/home/presley:/bin/bash
cfq219:x:1548:1552:J.R.R. Tolkien:/home/tolkien:/bin/bash
nwk409:x:1541:1545:George Washington:/home/washington:/bin/bash
Script Execution (Part A)
Since the fox machines do not have useful /etc/passwd files (no first and last names), you will use the one provided with this assignment. Your submission will include a bash file (assign3A.sh) with exactly one line in it (you do not need a shebang) and should take the path to the passwd file as the first argument. Do not include an awk file or any other files besides assign3A.sh.

$ assign3A.sh /path/to/passwd

Part B
For this part of the assignment, you will only use the utilities covered in class so far (primarily awk) to create a program for printing user process information. Do not use Python or any programs/utilities not covered in class.

Your program should take the output from ps -ef and print the following for each user having a username matching the abc123 format:

Username
List of commands
After listing statistics for each user, the program should print the following information for all users having a username matching the abc123 format:

Line with earliest start time
Line with latest start time
Do not use sed, Python, or any other languages/utilities not covered in class.

Example
The example below is an excerpt from the ps -ef command which your program should be able to take as input. Note that if a process began execution on a previous calendar day, its STIME value will not be in the usual “hours and minutes” format, but rather in “month and day” format. This should be accounted for properly, and thus a simple text/numerical comparison will not suffice.

Input:

UID
PID PPID C STIME TTY
TIME CMD
adz110
5344 5334 0 08:47 pts/2
00:00:00
bash
dmq292
6908 6854 0 Jun04 pts/1
00:00:00
bash
adz110
7227 7150 0 Jul11 pts/9
00:00:00
who
erg474
7466 7461 0 08:54 pts/10
00:00:00
ls
dmq292
7966 7960 0 Jun04 pts/13
00:00:00
assign1.sh if of
xle135
8983 8636 0 08:59 pts/15
00:00:00
ssh ctf.cs.utsarr.net
zeh458
9057 1980 0 08:59 pts/7
00:00:00
vim prog.c
rslavin
9150 9139 0 08:59 pts/16
00:00:00 ps -af
xle135
8636 8628 0 08:58 pts/15
00:00:00 bash
 

Output:

User: adz110

bash who

User: dmq292

bash assign1.sh if of

User: erg474

ls

User: xle135

bash

ssh ctf.cs.utsarr.net

User: zeh458

vim prog.c

Earliest Start Time :

dmq292                          6908 6854 0 Jun04 pts/1
00:00:00 bash
Latest Start Time :

xle135                             8983 8636 0 08:59 pts/15
00:00:00 ssh ctf.cs.utsarr.net
Also, if there is a tie for earliest or latest start times, take the one with the UID that comes first alphabetically.

Hint: Consider using sort to help with grouping.

Script Execution (Part B)
Your program should each be invoked through a single bash file (see below) with input taken from stdin. The resulting output should be printed directly to stdout.

$ assign3B.sh < ps.in

or

$ ps -ef | assign3B.sh

Assignment Data
Sample input files can be found in:

/usr/local/courses/ssilvestro/cs3423/Fall19/assign3.

Script Files
Your submission should consist of multiple files:

sh - a bash script with a single line of code (i.e., one command) for part A
sh - a bash script to invoke for part B.
awk - the awk program used in assign3B.awk
Verifying Your Programs
Part A can be tested with the sample input provided with passwd.in.

Part B can be tested with the sample input provided with ps.in. Your program should also work with arbitrary input from the ps -ef command.