Appearance
Week 02 Laboratory (with solutions)
Objectives
- Understanding use of UNIX pipelines
- Understanding use of UNIX filters (sed, sort, uniq, cut, tr)
Preparation
Before the lab you should re-read the relevant lecture slides and their accompanying examples.
Getting Started
If you're not working at CSE, you can download the provided files as a zip file or a tar file.
Exercise: Sorting UNSW Enrolments
The file enrolments.psv contains a list of fake CSE enrolments.
The file enrolments.psv has 9 columns of data (columns are pipe separated):
UNSW Course Code
UNSW zID
Name
UNSW Program
UNSW Plan
WAM
UNSW Session
Birthdate
Sex
Each row of data represents one enrolment.
Exercise 1.1
Write the sort and the head or tail commands needed to print the enrolment for the student with the lowest zID.
If the student with the lowest zID has multiple enrolments, print their enrolment in the course with the highest Course Code.
It should print:
COMP9414|5200002|Tran Joel, Steven Brian Ben |3784/3|MECHAH|074.003|23T2|20010111|MNote that this is one line.
The line is probably to long to display without wrapping in most browsers.
The same is true for the other parts of this activity.
For a better view, copy the expected output into a text editor.
Sample Answer:
sort -t'|' -k2,2 -k1,1r enrolments.psv | head -1Approach:
Sort using '|' as the field delimiter.
Sort by zIDs(col 2).
Grab the lowest (first) zID (head).
Note: -kx,y means start sorting on xth column and stop sorting end of yth column
Exercise 1.2
Write the sort and the head or tail commands needed to print the first 100 enrolments ordered first by Course Code, then by zID.
It should print:
<div class="highlight">
BINF3010|5201804|Wong, Nathan Yuxuan |3778/3|COMPAS|037.997|23T2|20000214|M
BINF3010|5202234|Zhao, Harry |8543|DPBSA1|073.089|23T2|19970905|M
BINF3010|5204248|Tan Angus, Andre Oscar Md |3778/1|SENGAH|036.699|23T2|19981217|M
BINF3010|5206611|Zhang, Ethan Jay Josh |8543|COMPA1|051.641|23T2|19991101|M
BINF3010|5207861|Chen, Elizabeth Vanessa Michelle |8543|COMPA1|056.589|23T2|19841203|F
BINF3010|5209846|Zhang, Nicholas |8543|COMPA1|068.062|23T2|20020721|M
BINF3010|5209994|Gupta, Jesse Jason |3768/4|SENGAH|051.538|23T2|20030205|M
BINF3010|5212733|Liang, Yifan |3707/4|COMPCS|047.897|23T2|20030116|M
BINF3010|5217703|Wang, Michael Antonio |8543|COMPA1|051.995|23T2|20021001|M
BINF3010|5218071|Tan, Angela Kelly Hannah |3784/3|COMPSS|060.166|23T2|19911004|F
BINF3010|5218274|Chen, Darren Sam Luke |3707/2|DPBSA1|083.761|23T2|19980318|M
BINF3010|5223005|Phan, Adrian Christopher |3784/3|BIOMDS|067.008|23T2|20031201|M
BINF3010|5227026|Li, Ryan Haoran Felix |8543|COMPA1|095.598|23T2|20010504|M
B INF3010|5232551|Qian, Alexander Ibrahim Louis |3707/1|ELECAH|072.755|23T2|19921123|M
BINF3010|5237535|Nguyen, Michael |3778/3|COMPCS|057.865|23T2|20030624|M
BINF3010|5237727|Cao, Cheng Jordan Zac |3762/2|BIOMDS ELECAH|068.501|23T2|19980724|M
BINF3010|5239503|Liu, Jessica |8543|COMPA1|037.452|23T2|19941212|F
BINF3010|5240138|Lim, Tristan Ivan Tsz Jacob |3785/2|COMPY1|039.284|23T2|19970720|M
BINF3010|5244983|Li, Ryan Joel |8543|COMPA1|080.377|23T2|19970304|M
BINF3010|5245695|He, Chun |7004/1|ENGGAH|067.036|23T2|20010207|M
BINF3010|5245941|Xu, Haotian Arnav Leo |3768/1|SENGAH|041.633|23T2|20050405|M
BINF3010|5246049|He, Peter |7004/1|SENGAH|087.590|23T2|19980816|M
BINF3010|5248646|Wang, Jessica Rachel |8543|COMPA1|045.217|23T2|20031118|F
BINF3010|5249320|Du, Amy Jing Yu |3133/4|BIOMDS MECHAH|073.698|23T2|19990312|F
BINF3010|5249555|Wang, Eric Yang |8543|COMPA1|067.363|23T2|19960220|M
BINF3010|5251112|Huang, Luke Isaac Ruiqi |3778/1|SENGAH|082.871|23T2|19981025|M
BINF3010|5251256|Smith, Liam Bohan |3785/1|ELECAH|060.653|23T2|19970916|M
BINF3010|5252013|Zhao, Isaac |3784/1|COMPAS|066.212|23T2|19980930|M
BINF3010|5253443|Song Yuhan, Alice Winnie |3785/2|DPENX1|032.704|23T2|20030911|F
BINF3010|5257134|Chan, Hannah |3778/2|SENGAH|073.933|23T2|20030202|F
BINF3010|5258182|Fan, Tim Eric |7004/1|COMPAS COMPSS|073.095|23T2|20010925|M
BINF3010|5260129|Huynh, Karen |3785/3|ELECAH|073.287|23T2|20000512|F
BINF3010|5263438|K im Michael, Liam Timothy |3764/1|COMPCH|046.753|23T2|20030213|M
BINF3010|5263620|Yang, Ryan Ze |3707/1|COMPA1|070.901|23T2|19981021|M
BINF3010|5264102|Chen, Alex Chris Gabriel |8543|COMPA1|080.160|23T2|19990605|M
BINF3010|5266002|Ma, Adrian |1650|COMPY1|019.855|23T2|20010522|M
BINF3010|5267625|Chan, Mitchell Peter Harrison Gordon |8543|MTRNAH|065.261|23T2|19960526|M
BINF3010|5268496|Chen, Yi Sebastian |3789/4|COMPAS|052.445|23T2|19920629|M
BINF3010|5272109|Lin Aditi, Catherine Vivian |3707/4|COMPSS|096.447|23T2|20040903|F
BINF3010|5272404|Nguyen, Dylan Benjamin Tristan |1650|COMPA1|032.872|23T2|20000416|M
BINF3010|5276965|Park, Tony Anish |3674/2|UNDL-U|050.429|23T2|20010310|M
BINF3010|5289021|Wang, Ryan Jonathan Gordon |8543|COMPA1|073.166|23T2|1 9990202|M
BINF3010|5290699|Hu, Luke Ivan Danny |3785/1|COMPA1|046.852|23T2|19991029|M
BINF3010|5295319|Wang, Michael Jia |8543|COMPA1|058.703|23T2|19921120|M
BINF3010|5297819|Nguyen, Ryan Josh Ayush |3707/1|COMPA1|052.193|23T2|20001111|M
BINF9010|5202701|Yin, Xin Jessica |3783/2|CEICAH|061.013|23T2|19861112|F
BINF9010|5228372|Wang, William Felix |8543|COMPA1|051.552|23T2|20000307|M
BINF9010|5229328|Xu, Alexander Ricky Nathaniel Zac Matthew |3778/3|COMPCS|043.644|23T2|20010904|M
BINF9010|5232791|Ding, Derek Chun Will |3783/1|ACTLE1 COMPA1|080.907|23T2|19991228|M
BINF9010|5266930|Le, Andrew Jimmy Kenneth Mohammed |3778/3|COMPAS|083.830|23T2|19950921|M
BIOM1010|5205212|Zhang Yuxuan, Jason Sean Bowen Zhou |8543|COMPA1|089.914|23T2|20040220|M
BIOM1010|5206606|Wang, Jessica Katherine Emily Sarah |3707/1|COMPA1|049.001|23T2|20000309|F
BIOM1010|5206630|Xiong Sophie, Jessica Winnie Olivia |3738/1|COMPD1 FINSA1|037.897|23T2|19901113|F
BIOM1010|5206723|Patel, Jiahao Angus |3674/1|COMPQS|028.951|23T2|19960526|M
BIOM1010|5207058|Lu, James Nathaniel Jun |3784/2|COMPCS|036.779|23T2|20020209|M
BIOM1010|5207762|Yu, Xin Sophie Ashley |1650|MECHAH|057.132|23T2|19990127|F
BIOM1010|5207793|Huang, Aiden Laurence |8543|DPHUB1|065.937|23T2|20020526|M
BIOM1010|5210902|Hua, Jimmy Danny |3736/1|CRIMA1|069.992|23T2|20030329|M
BIOM1010|5213983|Yin, Xinyi Jiayu Amanda |1650|AEROAH|069.873|23T2|20040806|F
BIOM1010|5217184|Luo, Tiffany Grace |3970/1|COMPA1 MTRNAH|078.933|23T2|19991211|F
BIOM1010|5219063|Huynh, Jordan Cheng |3673/4|ACTLD1 COMPA1|067.054|23T2|20040201|M
BIOM 1010|5221130|Xu Xin, Megan Yan |3778/2|COMPA1|047.261|23T2|19900504|F
BIOM1010|5222251|Fu, Zhou |3767/3|COMPS1 TELEAH|079.677|23T2|19971002|M
BIOM1010|5222829|Khan, Tim Stephen |8959|MTRNES|039.141|23T2|20011022|M
BIOM1010|5223425|Feng, Lachlan Jia |3706/1|BINFAH|029.145|23T2|20000828|M
BIOM1010|5225537|Wu, Han Christopher |3707/1|COMPA1|046.467|23T2|19891023|M
BIOM1010|5226090|Fu Jenny, Natalie Tiffany Ashley |3784/1|COMPZ1|059.421|23T2|20000725|F
BIOM1010|5227987|Luo, Brandon Jack |3707/2|COMPAS COMPCS|074.718|23T2|20031109|M
BIOM1010|5234944|Xu, Tom |3785/1|DPBSA1|071.419|23T2|19990921|M
BIOM1010|5235284|Luo, Zihao Jian Isaac |3707/4|COMPCS|047.997|23T2|20050721|M
BIOM1010|5240207|Tang, Winnie Xinyue |3768/4|UNDL-U|085.521|23T2|19991214|F
BIOM1010|5244252|Liu Katherine, Jessica |8543|COMPA1|088.472|23T2|20050812|F
BIOM1010|5244507|Kim, Han Ryan |3673/2|COMPES|066.370|23T2|19960115|M
BIOM1010|5244938|Zhang, Jessica Vanessa |8543|COMPA1|093.235|23T2|20000315|F
BIOM1010|5245298|Lu, Andrew Jiawei |3784/1|MTRNAH|042.124|23T2|19990809|M
BIOM1010|5246919|Yu, Andy Gabriel |3784/1|MECHAH|057.784|23T2|20040801|M
BIOM1010|5247276|Ma, Dylan |3778/1|COMPA1|028.814|23T2|20020906|M
BIOM1010|5248871|Zou William, Jiayi Andrew Hugo Yang |3783/1|COMPD1|066.684|23T2|20010720|M
BIOM1010|5249915|Liu, Andy Jordan |8543|COMPA1|052.561|23T2|19980927|M
BIOM1010|5250595|Yang Vivian, Angela |3778/2|COMPA1|058.900|23T2|20001105|F
BIOM1010|5251436|Shen, Moham mad Laurence |7003/1|SENGAH|068.050|23T2|20000710|M
BIOM1010|5252076|Ma, Benjamin George |7001/1|COMPD1|019.147|23T2|20001203|M
BIOM1010|5252677|Wang, Andrew Max |8543|COMPA1|031.697|23T2|19960927|M
BIOM1010|5255168|Nguyen Robert, Luke Henry |3961/1|COMPAS INFSKS|062.165|23T2|19871029|M
BIOM1010|5255953|Yu, Hannah |3778/2|UNDL-U|037.419|23T2|20040128|F
BIOM1010|5255975|Duan, Ray Jian Jonathan |3962/1|COMMJ1 COMPD1|046.259|23T2|19940727|M
BIOM1010|5258536|Ng, Zihao Austin Ayush |3674/2|ELECAH|055.967|23T2|19950803|M
BIOM1010|5259131|Zhang Charlotte Elizabeth, Anna Alicia Lara Christ|8543|COMPA1|066.881|23T2|20020612|F
BIOM1010|5264771|Lim, David |3674/1|DPENX1|066.111|23T2|19991026|M
BIOM1010|5267838|Fu, Cindy Hannah |3061/1|DDESB1 MDIA R2|030.681|23T2|20020326|F
BIOM1010|5269780|Zhang, Angela Yan |8543|COMPA1|084.410|23T2|20010429|F
BIOM1010|5270784|Liao Jerry, Jonathan Liam |8338|COMPA1 MATHA1|082.284|23T2|20040625|M
BIOM1010|5275340|Wang Thomas, Matthew |3707/1|COMPA1|065.881|23T2|19870726|M
BIOM1010|5275746|Gong, Timothy Hugo |3768/3|CEICAH|032.200|23T2|19860410|M
BIOM1010|5279455|Yang, Jack Joel |3784/2|COMPER|090.653|23T2|20000407|M
BIOM1010|5279645|Wang, William |8543|COMPA1|079.799|23T2|19800122|M
BIOM1010|5280127|Tang Andy, Brian Dylan |3707/4|COMPSS|043.828|23T2|20040213|M
BIOM1010|5282285|Tao, Steven |8750/1|MATHNS|057.091|23T2|19910919|M
BIOM1010|5282675|Lai, Yu Emma Lara |3782/1|BINFAH|099.858|23T2|20040612|F
BIOM1010|5283612|Khan Jessica, Lucy Xiny ue Michelle |3784/3|DPENX1|080.405|23T2|20040921|F
</div>
Sample answer:
```
sort -t'|' -k1,2 enrolments.psv | head -100
```
Approach:
Sort using '\|' as the field delimiter.
Sort by course codes(col 1) and then zIDs(col 2).
Grab the lowest (first) enrolments (`head`).
Note: -kx,y means start sorting on xth column and stop sorting end
of yth column
As always autotests are available
```
2041 autotest sorting_enrolments Q2
```
Write the
sortand theheadortailcommands needed to print the first 50 enrolments ordered first byBirthdate, then byCourse Code, then byZid.It should print:
COMP9313|5282134|Li, Christopher Oliver Joel |3778/2|COMPCS|061.069|23T2|19570918|M COMP9417|5289452|Nguyen, Joshua Terry |3778/2|COMPCS|041.749|23T2|19570918|M DPGE1002|5289452|Nguyen, Joshua Terry |3778/2|COMPCS|041.749|23T2|19570918|M COMP1511|5236538|Trinh, Yan Natalie |3707/1|COMPBH|021.732|23T2|19590220|F COMP4952|5236538|Trinh, Yan Natalie |3707/1|COMPBH|021.732|23T2|19590220|F COMP9417|5284939|Mei, Frank Aust in |3764/2|COMPA1 MTRNAH|067.113|23T2|19590220|M COMP9900|5250145|Zhao, Victor Gordon |3778/1|COMPCS|083.041|23T2|19590220|M DPBS1120|5284939|Mei, Frank Austin |3764/2|COMPA1 MTRNAH|067.113|23T2|19590220|M COMP3153|5276435|Liu, Grace Joyce |8543|COMPA1|061.354|23T2|19620722|F COMP6452|5276435|Liu, Grace Joyce |8543|COMPA1|061.354|23T2|19620722|F COMP9312|5276435|Liu, Grace Joyce |8543|COMPA1|061.354|23T2|19620722|F COMP9444|5286618|Wang, Victoria Aditi Jing Jennifer Alicia Jennifer|3707/1|ELECAH|045.011|23T2|19620722|F DPGE1002|5240982|Xiao Tiffany, Emily |3673/3|COMPI1 ELECAH|043.846|23T2|19620722|F COMP1531|5287908|Mu, Dhruv James Patrick |3782/4|ACCTA1 FINSA1|061.189|23T2|19630823|M COMP4601|5215280|Huang, Richard Hugo Isaac |3778/3|COM PA1|087.705|23T2|19630823|M COMP9024|5287908|Mu, Dhruv James Patrick |3782/4|ACCTA1 FINSA1|061.189|23T2|19630823|M COMP9417|5215280|Huang, Richard Hugo Isaac |3778/3|COMPA1|087.705|23T2|19630823|M COMP9444|5263308|Lee, Chris Louis |8543|COMPA1|056.191|23T2|19630823|M DPGE1001|5243700|Wei, Adrian |3791/3|ELECAH|093.170|23T2|19630823|M DPGE1002|5215280|Huang, Richard Hugo Isaac |3778/3|COMPA1|087.705|23T2|19630823|M DPST1031|5209031|Nguyen Lisa, Sarah Christine Amy Jiayu Emma |8543|COMPA1|074.454|23T2|19630823|F COMP1531|5217454|Lee, Xin Victoria |3778/2|COMPA1|084.053|23T2|19661218|F COMP9021|5217454|Lee, Xin Victoria |3778/2|COMPA1|084.053|23T2|19661218|F COMP9024|5263205|Li Gregory, Oliver |3785/1|COMPCS|070.453|23T2|19661218|M COMP9312|5263205|Li Gregory, Oliver |3785/1|COMPCS|070.453|23T2|19661218|M COMP1511|5278327|Kim, Hao Ray |3778/1|SENGAH|074.695|23T2|19681109|M COMP1521|5249383|Li, Luke |3778/2|COMPA1|052.228|23T2|19681109|M COMP1911|5222418|Yang, Matthew Nicholas |8543|COMPCS|070.222|23T2|19681109|M COMP2041|5278327|Kim, Hao Ray |3778/1|SENGAH|074.695|23T2|19681109|M COMP2521|5249383|Li, Luke |3778/2|COMPA1|052.228|23T2|19681109|M COMP3121|5280978|Zhang, Emily Charlotte Catherine Chloe Christine |8543|COMPA1|056.223|23T2|19681109|F COMP3900|5280978|Zhang, Emily Charlotte Catherine Chloe Christine |8543|COMPA1|056.223|23T2|19681109|F COMP6452|5249383|Li, Luke |3778/2|COMPA1|052.228|23T2|19681109|M COMP9331|5280978|Zhang, Emily Charlotte Catherine Chloe Christine |8543|COMPA1|056.223|23T2|19681109|F COMP941 7|5278327|Kim, Hao Ray |3778/1|SENGAH|074.695|23T2|19681109|M DPBS1120|5280433|Chen Rui, Aryan |3778/3|COMPAS|082.709|23T2|19681109|M DPST1013|5280978|Zhang, Emily Charlotte Catherine Chloe Christine |8543|COMPA1|056.223|23T2|19681109|F COMP1511|5265057|Wan, Chun Jin Samuel |3767/3|DPHUD1|038.415|23T2|19690307|M COMP1521|5201661|Yang, Joshua Tsz David |3778/1|SENGAH|066.655|23T2|19690307|M COMP1521|5289463|Zhao, Andrew Karan Arjun |7004/1|SENGAH|064.292|23T2|19690307|M COMP1531|5216127|Geng, Yan Ken |3956/1|BIOMBS|080.077|23T2|19690307|M COMP2041|5201661|Yang, Joshua Tsz David |3778/1|SENGAH|066.655|23T2|19690307|M COMP3141|5265057|Wan, Chun Jin Samuel |3767/3|DPHUD1|038.415|23T2|19690307|M COMP3141|5289463|Zhao, Andrew Karan Arjun |7004/1|SE NGAH|064.292|23T2|19690307|M COMP9020|5289463|Zhao, Andrew Karan Arjun |7004/1|SENGAH|064.292|23T2|19690307|M COMP9414|5216127|Geng, Yan Ken |3956/1|BIOMBS|080.077|23T2|19690307|M COMP1521|5219286|Guo, Joyce Karen |8338|COMPAS|067.357|23T2|19691224|F COMP1911|5250938|Lin Zheng, Oliver |3959/3|COMPAS COMPSS|060.545|23T2|19691224|M COMP3511|5250938|Lin Zheng, Oliver |3959/3|COMPAS COMPSS|060.545|23T2|19691224|M COMP1511|5268502|Hoang, Stephen Tao Minh Samuel |1650|ECONI1 MTRNAH|057.305|23T2|19700119|MSample answer:
sort -t'|' -k8,8 -k1,2 enrolments.psv | head -50Approach: < /p>
Sort using '|' as the field delimiter.
Sort by birthdates (col 8).
Then sort by course codes(col 1) and then zIDs(col 2).
Grab the lowest (first) enrolments (head).Note: -kx,y means start sorting on xth column and stop sorting end of yth column
As always autotests are available
2041 autotest sorting_enrolments Q3Write the
sortand theheadortailcommands needed to print the first 25 enrolments ordered first by the decimal part of theWAMin descending order, then byzIDin ascending order, then byCourse Codealso in ascending order.It should print:
COMP1511|5212432|Wang, Chloe Amanda Yu |8543|COMPA1|062.999|23T2|19960408|F COMP9313|5215738|Nguyen, Max |3707/1|COMPA1|081.999|23T2|19920915|M COMP9417|5215738|Nguyen, Max |3707/1|COMPA1|081.999|23T2|19920915|M COMP3141|5219983|Zhu, Rachel Grace |8543|DPBSA1|078.999|23T2|19980225|F DPGE1002|5219983|Zhu, Rachel Grace |8543|DPBSA1|078.999|23T2|19980225|F DPBS1150|5225868|Wong, Yu Xinyue |3707/1|SENGAH|062.999|23T2|19940626|F COMP9444|5226001|Sharma, Aryan Zachary Francis |3768/3|ELECAH|078.999|23T2|19871129|M DPGE1003|5226001|Sharma, Aryan Zachary Francis |3768/3|ELECAH|078.999|23T2|19871129|M COMP2041|5235855|Jiang, Jesse Pranav |3768/4|COMPAH|058.999|23T2|19990220|M COMP1511|5250497|Liu, Emily Karen |8543|COMPA1|060.999|23T2|20010423|F COMP1531|5250497|Liu, Emily Karen |8543|COMPA1|060.999|23T2|20010423|F COMP9444|5250497|Liu, Emily Karen |8543|COMPA1|060.999|23T2|20010423|F DPBS1140|5250497|Liu, Emily Karen |8543|COMPA1|060.999|23T2|20010423|F COMP9444|5251974|Lee, Nicole Rachel |7004/1|COMPAS|048.999|23T2|19970104|F COMP3121|5263804|Huang, Alice |3778/3|COMPAS|034.999|23T2|19971203|F DPGE1003|5263804|Huang, Alice |3778/3|COMPAS|034.999|23T2|19971203|F COMP1521|5281281|Wang, Anna Sophia |8543|COMPA1|010.999|23T2|20050530|F COMP3900|5281281|Wang, Anna Sophia |8543|COMPA1|010.999|23T2|20050530|F DPGE1002|5281281|Wang, Anna Sophia |8543|COMPA1|010.999|23T2|20050530|F COMP1531|5215378|Wu, Samuel Zihao |3778/2|COMPCS|096.998|23T2|19940626|M COMP6452|5251820|Guo, Zheng |3781/1|AEROAH|084.998|23T2|20031228|M COMP2521|5252367|Zhao, Edward |3707/2|MTRNAH|035.998|23T2|20050629|M COMP1511|5258610|Li, Daniel Yuhao |8543|COMPA1|071.998|23T2|19901016|M COMP1521|5262296|Qi, Zhou Yan Callum Yang |3784/2|MATHP1|064.998|23T2|20000629|M COMP2511|5262296|Qi, Zhou Yan Callum Yang |3784/2|MATHP1|064.998|23T2|20000629|MSample answer:
sort -t'|' -k6.5,6rn -k2,2n -k1,1 enrolments.psv | head -25Approach:
Sort using '|' as the field delimiter.
Sort by WAMs (col 6) from the fifth character to end of column 6, numerically and in reverse (to grab the highest decimals).
Then sort by zIDs (col 2) numerically.
Then sort by course codes (col 1).
Grab the lowest (first) enrolments (head).Note: -kx.z,y means start sorting on xth column from the zth letter and stop sorting end of yth column
As always autotests are available
2041 autotest sorting_enrolments Q4
Sample solution for sorting_enrolments_answers.txt
Exercise: Counting UNSW classes
There is a template file named counting_classes_answers.txt which you must use to enter the answers for this exercise.
The autotest scripts depend on the format of counting_classes_answers.txt so just add your answers don't otherwise change the file.
The file classes.tsv contains a list of CSE classes.
The file classes.tsv has 7 columns of data (columns are tab separated):
UNSW course code
UNSW class id
CSE class type
Number of enrolled students
Class enrolment cap
Class time
Class Location
Each row of data represents one class.
Write a shell pipeline which will print how many classes there are.
It should print:
1275Sample answer:
wc -l < classes.tsvApproach:
As each line in the file represents a class,
the number of classes is equal to the number of lines in the file.As always autotests are available
2041 autotest counting_classes Q1Write a shell pipeline which will print how many different courses have classes.
It should print:
75cut will be useful here.
Sample answer:
cut -f1 classes.tsv | sort | uniq | wc -lApproach:
Extract just the course codes (
cut).
Sort them into groups of identical course codes (sort).
Compress each group to size one, giving one line for each course (uniq).
Count the number of lines (wc).As always autotests are available
2041 autotest counting_classes Q2Write a shell pipeline which will print the course with the most classes, and how many classes are in this course.
If there are multiple courses with the same number of classes, print the course that is alphabeticaly first.
It should print:
84 COMP1511Sample answer:
cut -f1 classes.tsv | sort | uniq -c | sort -n | tail -1Approach:
Extract just the course codes (
cut).
Sort them into groups of identical course codes (sort).
Compress each group to size one and count the size of each group (uniq).
Sort by the size of each group (sort).
Grab the largest (last) group (tail).As always autotests are available
2041 autotest counting_classes Q3Write a shell pipeline which will print the two rooms most frequently used by non-LAB CSE classes and how often they are used.
If there are multiple rooms that are used by the same number of non-LAB CSE classes, print order them alphabeticaly.
It should print:
92 Online 28 Quad G054Sample answer:
grep -Fv 'LAB' classes.tsv | cut -f7 | sort | uniq -c | sort -nr | head -2Approach:
Extract the non-tut classes (
grep).
Extract just the room names (cut).
Sort them into groups of identical room names (sort).
Compress each group to size one and count the size of each group (uniq).
Sort by the size of each group (sort).
Grab the largest (first) group (head).As always autotests are available
< kbd is="sh">2041 autotest counting_classes Q4Write a shell pipeline which will print the most common day in the week and hour in the day for classes to start and how many classes start at that time.
If there are multiple days and times that are used by the same number of classes, print the day and time that is alphabeticaly first.
It should print:
48 Tue 14cut's
-doption will be useful here.Sample answer:
cut -f6 classes.tsv | cut -d'-' -f1 | cut -d':' -f1 | sort | uniq -c | sort -n | tail -1Approach:
Extract just the class times (
cut).
Remove the ending time (cut).
Sort them into groups of identical times (sort).
Compress each group to size one and count the size of each group (uniq).
Sort by the size of each group (sort).
Grab the largest (last) group (tail).As always autotests are available
2041 autotest counting_classes Q5 Write a shell pipeline which will print the latest time a class will finish. It should print: 21Sample answer:
cut -f6 classes.tsv | cut -d' ' -f2 | cut -d'-' -f2 | sort -un | tail -1Approach:
TODO.
As always autotests are available
2041 autotest counting_classes Q6Write a shell pipeline which will p rint a list of the course codes of COMP courses that run 2 or more classes of the same type starting at the same time on the same day.
(e.g. three tuts starting Monday at 10:00).It should print:
COMP1511 COMP1521 COMP1531 COMP1911 COMP2041 COMP2511 COMP2521 COMP3121 COMP3331 COMP3511 COMP3900 COMP6445 COMP6452 COMP6733 COMP6845 COMP9044 COMP9101 COMP9311 COMP9312 COMP9313 COMP9331 COMP9414 COMP9417 COMP9444 COMP9900Sample answer:
grep -F 'COMP' classes.tsv | cut -f1,3,6 | cut -d'-' -f1 | sort | uniq -d | cut -f1 | sort | uniqApproach:
TODO.
As always autotests are available
2041 autotest counting_classes Q7
When you think your program is working, you can use autotest to run some simple automated tests:
2041 autotest counting_classesWhen you are finished working on this exercise, you must submit your work by running give:
give cs2041 lab02_counting_classes counting_classes_answers.txtbefore Tuesday 27 February 12:00 (midday) (2024-02-27 12:00:00) to obtain the marks for this lab exercise.
Sample solution for counting_classes_answers.txt
This file is automarked.
Do not add extra lines to this file, just add your answers.
For example if your answer to Q0 is: "grep -E Andrew words.txt"
Change the line that starts with
"Q0 answer:"
to
"Q0 answer: grep -E Andrew words.txt"
------------------------------------------------------------------------------------------------------------------------
1) Write a shell pipeline which will print how many classes there are.
Q1 answer: wc -l < classes.tsv
2) Write a shell pipeline which will print how many different courses have classes.
Q2 answer: cut -f1 classes.tsv | sort | uniq | wc -l
3) Write a shell pipeline which will print the course with the most classes, and how many classes are in this course.
Q3 answer: cut -f1 classes.tsv | sort | uniq -c | sort -n | tail -1
4) Write a shell pipeline which will print the two rooms mos t frequently used by non-LAB CSE classes and how often they are used.
Q4 answer: grep -Fv 'LAB' classes.tsv | cut -f7 | sort | uniq -c | sort -nr | head -2
5) Write a shell pipeline which will print the most common day and hour in the week for classes to start and how many classes start at that time.
Q5 answer: cut -f6 classes.tsv | cut -d'-' -f1 | cut -d':' -f1 | sort | uniq -c | sort -n | tail -1
6) Write a shell pipeline which will print the latest time a class will finish.
Q6 answer: cut -f6 classes.tsv | cut -d' ' -f2 | cut -d'-' -f2 | sort -un | tail -1
7) Write a shell pipeline which will print a list of the course codes of COMP courses that run 2 or more classes of the same type starting at the same time on the same day. (e.g. three tuts starting Monday at 10:00).
Q7 answer: grep -F 'COMP' classes.tsv | cut -f1,3,6 | cut -d'-' -f1 | sort | uniq -d | cut -f1 | sort | uniq
Exercise: Editing C Source Files
There is a template file named editing_programs_answers.txt which you must use to enter the answers for this exercise.
The autotest scripts depend on the format of editing_programs_answers.txt so just add your answers don't otherwise change the file.
The file program.c contains a C library implementing some simple sorting algorithms.
Write a
sedcommand to change all thesortrelated functions fromV1toV2.
This includes all relevant comments.It should print:
#include "stdlib.h" #include <stddef.h> #include "bits/types.h" typedef int (*compar)(const void *, const void *); #define SWAP(a, b, size) \ do { \ size_t __size = (size); \ char *__a = (a), *__b = (b); \ do { \ char __tmp = *__a; \ *__a++ = *__b; \ *__b++ = __tmp; \ } while (--__size > 0); \ } while (0) /** * bubble_sort_V2 * dumb bubble sort using the stdlib::qsort interface * @param base pointer to start of array to be sorted * @param nmemb number of elements in array to be sorted * @param size number of bytes of each element * @param comparator function to compare two element */ void bubble_sort_V2 (void *base, size_t nmemb, size_t size, compar comparator) { // TODO: use better variable names. char *base_ptr = (char *)base; for (size_t loop_V1 = 0; loop_V1 < nmemb; loop_V1++) { for (size_ t loop_V2 = 1; loop_V2 < nmemb; loop_V2++) { if ((*comparator)((void *)(&base_ptr[loop_V2*size]), (void *)(&base_ptr[(loop_V2-1)*size])) < 0) { SWAP((void *)(&base_ptr[loop_V2*size]), (void *)(&base_ptr[(loop_V2-1)*size]), size); } } } } extern int strcmp(const char *s1, const char *s2); int cmpstringp(const void *p1, const void *p2) { return strcmp(*(char *const *)p1, *(char *const *)p2); } int cmpintp(const void *p1, const void *p2) { return (*(int *)p1 > *(int *)p2) - (*(int *)p1 < *(int *)p2); } extern int printf(const char *format, ...); int main(void) { // Test that our bubble sort is working properly int array[10] = {6, 8, 3, 2, 7, 0, 100, -66, 63, 44}; // TODO: make this array bigger bubble_sort_V2(array, 10, sizeof(int), cmpintp); for (size_t i = 0; i < 10; i++) printf("%d, ", array[i]); printf("\n"); return 0; } /** * selection_sort_V2 * selection sort using the stdlib::qsort interface * @param base pointer to start of array to be sorted * @param nmemb number of elements in array to be sorted * @param size number of bytes of each element * @param comparator function to compare two element */ void selection_sort_V2 (void *base, size_t nmemb, size_t size, compar comparator) { // FIXME: implement this function. (void) base, (void) nmemb, (void) size, (void) comparator; return; } /** * insertion_sort_V2 * insertion sort using the stdlib::qsort interface * @param base pointer to start of array to be sorted * @param nmemb number of elements in array to be sorted * @param size number of bytes of each element * @param comparator function to compare two element */ void insertion_sort_V2 (void *base, size_t nmemb, size_t size, compar comparator) { char *base_ptr = (char *)base; for (size_t i = 1; i < nmemb; i++) { while ((*comparator)((void *)(&base_ptr[i*size]), (void *)(&base_ptr[(i-1)*size])) < 0) { SWAP((void *)(&base_ptr[i*size]), (void *)(&base_ptr[(i-1)*size]), s ize); } } }Sample answer:
sed 's/sort_V1/sort_V2/' program.cApproach:
TODO
As always autotests are available
2041 autotest editing_programs Q1Write a
sedcommand to remove all single line comments starting withTODOorFIXME.It should print:
#include "stdlib.h" #include <stddef.h> #include "bits/ty pes.h" typedef int (*compar)(const void *, const void *); #define SWAP(a, b, size) \ do { \ size_t __size = (size); \ char *__a = (a), *__b = (b); \ do { \ char __tmp = *__a; \ *__a++ = *__b; \ *__b++ = __tmp; \ } while (--__size > 0); \ } while (0) /** * bubble_sort_V1 * dumb bubble sort using the stdlib::qsort interface * @param base pointer to start of array to be sorted * @param nmemb number of elements in array to be sorted * @param size number of bytes of each element * @param comparator function to compare two element */ void bubble_sort_V1 (void *base, size_t nmemb, size_t size, compar comparator) { char *base_ptr = (char *)base; for (size_t loop_V1 = 0; loop_V1 < nmemb; loop_V1++) { for (size_t loop_V2 = 1; loop_V2 < nmemb; loop_V2++) { if ((*comparator)((void *)(&base_ptr[loop_V2*size]), (void *)(&base_ptr[(loop_V2-1)*size])) < ; 0) { SWAP((void *)(&base_ptr[loop_V2*size]), (void *)(&base_ptr[(loop_V2-1)*size]), size); } } } } extern int strcmp(const char *s1, const char *s2); int cmpstringp(const void *p1, const void *p2) { return strcmp(*(char *const *)p1, *(char *const *)p2); } int cmpintp(const void *p1, const void *p2) { return (*(int *)p1 > *(int *)p2) - (*(int *)p1 < *(int *)p2); } extern int printf(const char *format, ...); int main(void) { // Test that our bubble sort is working properly int array[10] = {6, 8, 3, 2, 7, 0, 100, -66, 63, 44}; bubble_sort_V1(array, 10, sizeof(int), cmpintp); for (size_t i = 0; i < 10; i++) printf("%d, ", array[i]); printf("\n"); return 0; } /** * selection_sort_V1 * selection sort using the stdlib::qsort interface * @param base pointer to start of array to be sorted * @param nmemb number of elements in array to be sorted * @param size number of bytes of each element * @param comparator function to compare two element */ voi d selection_sort_V1 (void *base, size_t nmemb, size_t size, compar comparator) { (void) base, (void) nmemb, (void) size, (void) comparator; return; } /** * insertion_sort_V1 * insertion sort using the stdlib::qsort interface * @param base pointer to start of array to be sorted * @param nmemb number of elements in array to be sorted * @param size number of bytes of each element * @param comparator function to compare two element */ void insertion_sort_V1 (void *base, size_t nmemb, size_t size, compar comparator) { char *base_ptr = (char *)base; for (size_t i = 1; i < nmemb; i++) { while ((*comparator)((void *)(&base_ptr[i*size]), (void *)(&base_ptr[(i-1)*size])) < 0) { SWAP((void *)(&base_ptr[i*size]), (void *)(&base_ptr[(i-1)*size]), size); } } }Sample answer:
sed -E 's://\s*(TODO|FIXME).*$::' program.cApproach:
TODO
As always autotests are available
2041 autotest editing_programs Q2Write a
sedcommand to print all lines starting withextern.It should print:
extern int strcmp(const char *s1, const char *s2); extern int printf(const char *format, ...);Sample answer:
sed - n '/^\s*extern/p' program.cApproach:
TODO
As always autotests are available
2041 autotest editing_programs Q3Write a
sedcommand to replace allincludestatements using"``"with<``>.It should print:
#include <stdlib.h> #include <stddef.h> #include <bits/types.h> typedef int (*compar)(const void *, const void *); #define SWAP(a, b, size) \ do { \ size_t __size = (size); \ char *__a = (a), *__b = (b ); \ do { \ char __tmp = *__a; \ *__a++ = *__b; \ *__b++ = __tmp; \ } while (--__size > 0); \ } while (0) /** * bubble_sort_V1 * dumb bubble sort using the stdlib::qsort interface * @param base pointer to start of array to be sorted * @param nmemb number of elements in array to be sorted * @param size number of bytes of each element * @param comparator function to compare two element */ void bubble_sort_V1 (void *base, size_t nmemb, size_t size, compar comparator) { // TODO: use better variable names. char *base_ptr = (char *)base; for (size_t loop_V1 = 0; loop_V1 < nmemb; loop_V1++) { for (size_t loop_V2 = 1; loop_V2 < nmemb; loop_V2++) { if ((*comparator)((void *)(&base_ptr[loop_V2*size]), (void *)(&base_ptr[(loop_V2-1)*size])) < 0) { SWAP((void *)(&base_ptr[loop_V2*size]), (void *)(&base_ptr[(loop_V2-1)*size]), size); } } } } extern int strcmp(const char *s1, const c har *s2); int cmpstringp(const void *p1, const void *p2) { return strcmp(*(char *const *)p1, *(char *const *)p2); } int cmpintp(const void *p1, const void *p2) { return (*(int *)p1 > *(int *)p2) - (*(int *)p1 < *(int *)p2); } extern int printf(const char *format, ...); int main(void) { // Test that our bubble sort is working properly int array[10] = {6, 8, 3, 2, 7, 0, 100, -66, 63, 44}; // TODO: make this array bigger bubble_sort_V1(array, 10, sizeof(int), cmpintp); for (size_t i = 0; i < 10; i++) printf("%d, ", array[i]); printf("\n"); return 0; } /** * selection_sort_V1 * selection sort using the stdlib::qsort interface * @param base pointer to start of array to be sorted * @param nmemb number of elements in array to be sorted * @param size number of bytes of each element * @param comparator function to compare two element */ void selection_sort_V1 (void *base, size_t nmemb, size_t size, compar comparator) { // FIXME: implement this function. (void) base, (void) nmemb, (void) size, (void) comparator; return; } /** * insertion_sort_V1 * insertion sort using the stdlib::qsort interface * @param base pointer to start of array to be sorted * @param nmemb number of elements in array to be sorted * @param size number of bytes of each element * @param comparator function to compare two element */ void insertion_sort_V1 (void *base, size_t nmemb, size_t size, compar comparator) { char *base_ptr = (char *)base; for (size_t i = 1; i < nmemb; i++) { while ((*comparator)((void *)(&base_ptr[i*size]), (void *)(&base_ptr[(i-1)*size])) < 0) { SWAP((void *)(&base_ptr[i*size]), (void *)(&base_ptr[(i-1)*size]), size); } } }Sample answer:
sed -E 's/^#include\s+"([^"]*)"/#include <\1>/' program.cApproach:
TODO
As always autotests are available
2041 autotest editing_programs Q4Write a
sedcommand to remove themainmethod.It should print:
#include "stdlib.h" #include <stddef.h> #include "bits/types.h" typedef int (*compar)(const void *, const void *); #define SWAP(a, b, size) \ do { \ size_t __size = (size); \ char *__a = (a), *__b = (b); \ do { \ char __tmp = *__a; \ *__a++ = *__b; \ *__b++ = __tmp; \ } while (- -__size > 0); \ } while (0) /** * bubble_sort_V1 * dumb bubble sort using the stdlib::qsort interface * @param base pointer to start of array to be sorted * @param nmemb number of elements in array to be sorted * @param size number of bytes of each element * @param comparator function to compare two element */ void bubble_sort_V1 (void *base, size_t nmemb, size_t size, compar comparator) { // TODO: use better variable names. char *base_ptr = (char *)base; for (size_t loop_V1 = 0; loop_V1 < nmemb; loop_V1++) { for (size_t loop_V2 = 1; loop_V2 < nmemb; loop_V2++) { if ((*comparator)((void *)(&base_ptr[loop_V2*size]), (void *)(&base_ptr[(loop_V2-1)*size])) < 0) { SWAP((void *)(&base_ptr[loop_V2*size]), (void *)(&base_ptr[(loop_V2-1)*size]), size); } } } } extern int strcmp(const char *s1, const char *s2); int cmpstringp(const void *p1, const void *p2) { return strcmp(*(char *const *)p1, *(char *const *)p2); } int cmpintp(const voi d *p1, const void *p2) { return (*(int *)p1 > *(int *)p2) - (*(int *)p1 < *(int *)p2); } extern int printf(const char *format, ...); /** * selection_sort_V1 * selection sort using the stdlib::qsort interface * @param base pointer to start of array to be sorted * @param nmemb number of elements in array to be sorted * @param size number of bytes of each element * @param comparator function to compare two element */ void selection_sort_V1 (void *base, size_t nmemb, size_t size, compar comparator) { // FIXME: implement this function. (void) base, (void) nmemb, (void) size, (void) comparator; return; } /** * insertion_sort_V1 * insertion sort using the stdlib::qsort interface * @param base pointer to start of array to be sorted * @param nmemb number of elements in array to be sorted * @param size number of bytes of each element * @param comparator function to compare two element */ void insertion_sort_V1 (void *base, size_t nmemb, size_t size, compar comparator) { char *base_ptr = (char *)base; for (size_t i = 1; i < nmemb; i++) { while ((*comparator)((void *)(&base_ptr[i*size]), (void *)(&base_ptr[(i-1)*size])) < 0) { SWAP((void *)(&base_ptr[i*size]), (void *)(&base_ptr[(i-1)*size]), size); } } }Sample answer:
sed '/^int main/,/^}/d' program.cApproach:
TODO
As always autotests are available
2041 autotest editing_programs Q5
When you think your program is working, you can use autotest to run some simple a utomated tests:
2041 autotest editing_programsWhen you are finished working on this exercise, you must submit your work by running give:
give cs2041 lab02_editing_programs editing_programs_answers.txtbefore Tuesday 27 February 12:00 (midday) (2024-02-27 12:00:00) to obtain the marks for this lab exercise.
Sample solution for editing_programs_answers.txt
This file is automarked.
Do not add extra lines to this file, just add your answers.
For example if your answer to Q0 is: "grep -E Andrew words.txt"
Change the line that starts with
"Q0 answer:"
to
"Q0 answer: grep -E Andrew words .txt"
------------------------------------------------------------------------------------------------------------------------
1) Write a sed command to change all the functions from V1 to V2.
Q1 answer: sed 's/sort_V1/sort_V2/' program.c
2) Write a sed command to remove all single line comments starting with TODO or FIXME.
Q2 answer: sed -E 's://\s*(TODO|FIXME).*$::' program.c
3) Write a sed command to print all lines starting with extern.
Q3 answer: sed -n '/^\s*extern/p' program.c
4) Write a sed command to replace all include statements using "" with <>.
Q4 answer: sed -E 's/^#include\s+"([^"]*)"/#include <\1>/' program.c
5) Write a sed command to remove the main method.
Q5 answer: sed '/^int main/,/^}/d' program.c
Challenge Exercise: Exploring Regular Expression Extensions
There is a template file named advanced_ab_answers.txt which you must use to enter the answers for this exercise.
The autotest scripts depend on the format of advanced_ab_answers.txt so just add your answers don't otherwise change the file.
Use grep -P to test your answers to these questions.
These questions can't be solved using the standard regular expression language described in lectures.
The following commands may provide useful information:
man 1 grep
info grep
man 7 regex
perldoc perlreWe've provided a set of test cases in input.txt
Write a
grep -Pcommand that prints the lines in a file namedinput.txtcontaining only the charactersAandBsuch that there are exactly n A's followed by exactly n B's and no other characters.Matching AAABBB AB AABB AAAAAAAAAABBBBBBBBBB Not Matching AAABB ABBBBB AAAAAA AABBAB This can't be done with a POSIX regular expression.
You prove this via the the wonderfully named pumping lemma.It is possible with extensions to regular expressions, e.g. as provided in Perl and PCRE.
Sample answer:
grep -P '^(A(?1)?B)$' input.txtAs always autotests are available
2041 autotest advanced_ab
When you think your program is workin g, you can use autotest to run some simple automated tests:
2041 autotest advanced_abWhen you are finished working on this exercise, you must submit your work by running give:
give cs2041 lab02_advanced_ab advanced_ab_answers.txtbefore Tuesday 27 February 12:00 (midday) (2024-02-27 12:00:00) to obtain the marks for this lab exercise.
Sample solution for advanced_ab_answers.txt
This file is automarked.
Do not add extra lines to this file, just add your answers.
For example if your answer to Q0 is: "grep -E Andrew words.txt"
Change the line that starts with
"Q0 answer:"
to
"Q0 answer: grep -E Andrew words.txt"
------------------------------------------------------------------------------------------------------------------------
1) Write a grep -P command that prints the lines in a file named input.txt containing only the characters A and B such that there are exactly n A's followed by exactly n B's and no other characters.
Q1 answer: grep -P '^(A(?1)?B)$' input.txt
Submission
When you are finished each exercises make sure you submit your work by running give.
You can run give multiple times. Only your last submission will be marked.
Don't submit any exercises you haven't attempted.
If you are working at home, you may find it more convenient to upload your work via give's web interface.
Remember you have until Week 3 Tuesday 12:00:00 (midday) to submit your work.
You cannot obtain marks by e-mailing your code to tutors or lecturers.
You check the files you have submitted here.
Automarking will be run by the lecturer several days after the submission deadline, using test cases different to those autotest runs for you. (Hint: do your own testing as well as running autotest.)
After automarking is run by the lecturer you can view your results here. The resulting mark will also be available via give's web interface.
Lab Marks
When all components of a lab are automarked you should be able to view the the marks via g ive's web interface or by running this command on a CSE machine:
2041 classrun -sturec