Lecture 1: Course Overview + The Shell (2020)

You can find the lecture notes and exercises for this lecture at missing.csail.mit.edu/2020/co...
Help us caption & translate this video!
amara.org/v/C1Efe/

[@litchyarn]

6:04 shell prompt 6:32 curstermizing shell 7:03 $date 7:19 $echo 7:29 $echo hello 7:46 $echo "Hello world" 8:41 10:01 environment variable 10:17 $echo $PATH 11:01 $ which echo 12:30 relative path 12:50 $pwd (print working directory) 13:24 cd /home (change my directory) 13:58 dot 15:03 ../../../../../ 16:20 $ls 17:15 ~ tild 17:36 - dash $ cd - 20:09 d means directory 21:32 read, write, execute 24:32 mv (rename, move) 25:20 cp (copy from, to) 25:50 rm (remove) 26:15 rmdir, mkdir (remove directory, make directory) 26:50 man (manual) 27:55 Ctrl+L (clear shall) 28:30 input and output 29:30 $echo hello > hello.txt 29:59 $cat hello.txt 30:10 $cat < hello.txt 30:43 $cat < hello.txt > hello2.txt 31:15 $>>^C 31:50 pipe 32:20 tail $tail -nl $ls -l / | tail -nl $ls -l / | tail -nl > ls.txt 33:35 curl curl --head --silent google.com curl --head --silent google.com | grep -i content-length curl --head --silent google.com | grep -i content-length | cut --delimetr = ' ' -f2 36:39 $sudo (super user) 38:02 $cat brightness $sudo echo 500 > brightness

[@skandamahesh9974]

Jeong Rita thanks man really helps

[@lucaban]

this needs more upvotes!!!

[@Mainmenify]

Well done! this absolutely needs to be added to the video description to show timespamps on the video progress bar!!!

[@DrHusseinAlOmari]

Thank you! Very useful!

[@hingsli7245]

good job man, very helpful!

[@samdavepollard]

i'm old; i graduated in 1979, way before the www was a thing the fact that i can hop onto youtube and drop into a class at MIT like this still blows my mind

[@upstatenetworks4639]

Similar. EE/CS 1980's We've passed files back and forth for decades. Our development projects now involve 10's of programmers. This lecture was well presented and gratefully received. Nice Job and Thank you!

[@edvaned8207]

Similiar too. i graduated in 2004 😁

[@ShivangiSingh-wc3gk]

I feel so dumb at work sometimes. I had to learn these things the hard way, thank you for putting this out there.

[@xBugzilla]

But #! is a special comment, not telling the shell to run as root, right? I don’t get your comment or maybe I missed the part he explained shebang

[@resulhangeldiyev4427]

thank you youtube algorithm for this magnificent content

[@fedeac31]

I think we should rather thank MIT. They're quite probably the best tech university in the world, and they're publishing content for free that they could charge us a fortune to access if they wanted to.

[@mrmusicdu74]

Why is this in my recommandations and why am I starting to plan to watch the whole courses

[@qwerty-wt5dr]

+1 I even dont have Linux installed for years

[@zounoaa9689]

same!

[@aalbero]

long live KZbin recommendations

[@sadeepthabandara8117]

If you haven't already, go for it!

[@overglobe]

😂

[@Chr0nalis]

I've been writing "clear" instead of just ctrl+l all this time ..

[@love.ly.]

Teymur Azayev same 😮

[@wolfram77]

is there a shortcut to clear scrollback too?

[@rabingaire]

same here

[@aavocadoToast]

Same

The clear command and ctrl+l do not do the same thing. They are very similar, but sometimes it makes sense to use one or the other.

[@Milbrown_Worker]

Im sad this kind of quality instruction is not commonplace across other post secondary institutions.. I guess it is MIT after all... Thanks for making this available

[@yousifabdulhussein]

This type of quality instruction isn’t even commonly available at MIT lol.

[@yixe2253]

These lecture are amazing, thanks for releasing this to the public!

[@ChristopherOkhravi]

This.

[@skarasif]

@@ChristopherOkhravi lectures ;-)

[@v1r47]

@@skarasif lectures* :-)

[@driden1987]

@@ChristopherOkhravi are you planning on coming back to creating videos on YT? Really wanted to see how your VIM series would pan out. Thanks for everything

[@terrence369]

Very true

[@dhruvgupta8751]

the xdg-open in powershell was just: start worked with pdfs and .html files.

[@middleverse3838]

I'm like 15 minutes in, and I'm already thankful to you guys for making this!! For someone who used to be a programmer but left and is now making a comeback, this packs-a-punch.

[@harshdeepsingh1026]

How they teach and covers the topic is really helpful. I think they are doing great work to post these and their notes over internet for people to use. Regards to the authors.

[@loremipsum7513]

THIS IS WHAT WE ALL NEEDED. THANK YOU FROM THE BOTTOM OF MY HEART.

[@shelinesim1038]

"On Windows, who knows?" made me chuckle

[@pedrofalcao1900]

Made me install linux

[@ze_kel]

​@@pedrofalcao1900 try WSL it's super easy to setup and you get full linux terminal inside your windows.

[@HendersonHarrisson]

WSL easy bash without switching OSes

[@seonginna8804]

This is a lecture series I have wanted. Thank you MIT!

[@mlcmingliang]

43:44 scroll lock is for you to scroll around in spreadsheet program like Excel with arrow keys. so when it is toggled, arrow keys scroll around instead of move the focus on a cell

[@wolfram77]

that is also what ctrl+arrow keys do in a text editor. thanks for sharing.

[@tamat]

I cannot thank you enough for this course. Im also a teacher at the university and I never have the time to teach this concepts deeply to my students, so at least now I have a place to redirect them.

[@advitiayanand5974]

glad to hear there's teachers that still care.

[@walkastray007]

I'm actually tearing up. I've been trying to learn how to do things and it's been super frustrating and EVERY SINGLE COURSE I have ever seen either teaches you what a variable is. Or has a "google is your best friend" sort of approach. Thank you so much for making these videos

[@sciberbee]

I came to think again, that we are living very hopeful period of time given that these fruitful and friendly lectures from MIT is ready to be watched free, at all around the world:)

[@shreyaskali996]

great! MIT never ever dissapoints me. Hope this quality of education become a standard in the future in every country.

[@infinite-journey]

Lectures we didn't ask for but we all needed the most.

[@koraytugay]

Starts at 4:08

[@ivansakal1224]

cheers man

[@Hilaire_Balrog]

Thanks. Those late student were annoying me.

[@mustafaerdem140]

Tesekkurler

[@alexandrechen3081]

This is exactly what I need! Thank you MIT

[@fedeac31]

This is awesome. You guys are awesome for sharing it publicly. Everything about this is awesome.

[@PainfullySubjective]

so glad i found this courses. thank you MIT and all who made this!

[@StankyPickle1]

I wish this lecture series existed 6 years ago. Would've made life a little easier.

[@EndrChe]

This is the most beautiful thing I’ve ever found on KZbin...

[@JasonSFuller]

40:24 Please don't teach people "sudo su" (or the slightly less terrible "sudo su -"). In fact, don't teach people about "su" at all, other than to use it to install/fix "sudo" or as a history lesson. It certainly _works_, but you're telling the shell to do something twice, i.e. "run as root" (sudo) then "become the root user" (su). The thing you want is "sudo -i" or "initial login" (equivalent to "su -" and "sudo su -"), which tells sudo to start a shell *and* process the normal login scripts, e.g. .profile, .login, .bash_profile, etc. "Su"ing twice has a number of unexpected and irritating--though not insurmountable--side-effects for administrators (i.e. me, a linux admin for 20+ years), but it also causes trouble for an end-users since it strips their environment variables. "Sudo" handles this quite well (depending on your sudoers configuration), but "su" does not. This is problematic for things like preserving a non-root user's $SSH_AUTH_SOCK (maybe you want to use your ssh keys when you're root), or language preferences ($LANG), or $DISPLAY for GUI users, etc.

[@adammoore6594]

Thanks, that is useful :)

[@mwat56]

In case you need a shell (to do more than a single command) you'd call: sudo bash That avoids the problems mentioned above.

[@JasonSFuller]

@@mwat56 I'll politely disagree here. "sudo -i" does, in fact, give you a shell, AND it simulates a login the proper way. "sudo bash" suffers from the same environment problems as "sudo su"

Exactly. I was going to comment this, but you explained it much better than I could.

[@aram535]

If you don't need to go through "login" then 'sudo -s' will also work and just start up a new environment rather than login then env. For example 'sudo -s' will drop you into a root shell and 'sudo -u foo -s' will drop you into a shell for user 'foo'. Again without the login (.profile & .login). I recommend using "sudo -c 'command'", "sudo -s" and "sudo -u foo -sH" (-H sets the homedir for the user as well).

[@bsko3D]

what a great and generous idea to publish these lectures for everyone. Thank you!

[@yanlin9130]

Pretty good lecture, I wish it would be available when I was a freshman five years ago. Thanks for the hard work.

[@henryluo9380]

Thanks for sharing it. It's really helpful to someone like me who have never learnt these basic things.

[@popluss]

wow, this is very good! the content is really nice and the way he teaches it and structure the lecture is way better than what i had in college

[@surered4958]

I cannot believe how good of a professor this guy is. I wish I could learn software development and data science from him.

[@glizzdawiz]

He has his own KZbin channel, which I just discovered kzbin.info/door/_iD0xppBwwsrM9DegC5cQQ

[@wizard7314]

41:30 it was worth watching for me, just for this. Great example of why 'cat' with shell piping isn't sufficient to write to a system file. But you also don't want to elevate the whole shell to root privileges because it's inconvenient (especially when scripting) and because then everything will be executed with root privileges. Now I understand why tee exists. Cheers.

[@casedup]

Great Great Great! Been using bash shell foryears and you opened me up to other worlds man. These videos are so 👍

[@majoragan]

Just finished first lecture... Big thanks for this series!

[@user-ox9wq1gj5k]

Amazing to look at it during quarantine. Thank you very much!

[@EarthB00]

These are super useful. Making my way through them.

[@takreem.akhter]

Thank you youtube recommendations. This was beautiful! I am going to watch the whole course.

[@edavar6265]

Another resource I can reccomend on this topic is Learn Enough Command Line To Be Dangerous. It is a fun read with exercises.

[@lautoka63]

A good thing to be doing. I used to do something similar in my airline engineering career by running lunchtime classes for new young engineers. Much of the time people assume that others know as much as they do, without thinking how long and hard it was to acquire that knowledge.

[@Kruglord]

Hey, that's Jon Gjengset! He does the "Crust of Rust" videos here on KZbin, I had no idea he also taught these lectures, I only recognize him now after coming back again 2 years later.

[@metroboomin8895]

tip: watch on 1.5 speed if it suits your fancy, i find it helps me focus (also great lecture!!)

[@meojunior]

I really enjoy this course and learn a ton of foundation things. Thanks guys

[@shubxam]

Thank you so much for releasing this course in public. Just been through 1st lecture and content and the way you teach is very good.

[@jasonkwan4814]

I wish it would be available when I was a freshman one years ago. Thanks for the hard work.

[@ZhengQu]

It is never too late :)

[@jitpackjoyride]

lol, I was a freshman 4 years ago and much more experienced now and I’m still going to sit through these lectures 🤓

[@nairorokidul]

Another not obvious thing: Inside the shell CTRL + C is cancel, not copy. The most useful trick noone tells you is hitting the up arrow offers you the latest command you entered, and you can scroll up as much as you want by hitting up arrow.

[@geoafrikana]

Use Ctrl + Insert to copy Shift + Insert to paste

[@sportsfreund8430]

God damn, I had this bookmarked for way too long. Looking forward to going through the playlist! :)

[@rabingaire]

I love how this guy explains things, I am a long time subscriber of his channel his voice is just mesmerizing

[@linsanity626]

Rabin Gaire same! what's his channel name?

[@rabingaire]

@@linsanity626 channel link kzbin.info/door/_iD0xppBwwsrM9DegC5cQQ

[@mrbeats7434]

Very good. This teacher is first class. Thanks so much

[@sriranganayakulu8513]

Thanks MIT!! For these great lecture series

[@garysantos7053]

Just a note of added confusion: Apple replaced "bash" with "zsh" as the default shell in macOS Catalina While a number of Mac developers have already moved on to even more modern shells like Fish, zsh is more compatible with Bourne shell (sh) and mostly compatible with bash. THE VERGE/ By Tom Warren@tomwarren Jun 4, 2019, 4:27am EDT

[@xrafter]

Bash and zsh have the same syntax.

[@KonstantinDorichev]

I remembered the basics and did learn a few commands I didn't know. Thanks!

[@yuexiao4739]

Love this course! Really helped me on my work.

[@jamoinmoin]

wow so many small useful things that actually boost productivity, great lecture

[@Qladstone]

After several years of watching lectures in my off-work hours, this shall be my "graduation" class.

[@jerrys5387]

I hope my univ could have such courses, instead of assuming we already know

[@10riddles]

Super useful for graduates. Thanks a bunch.

[@aavocadoToast]

Absolutely amazing lecture. I already knew 80% of these commands but it was still fun to watch and a good learning experience. Especially the fun stuff with sys directory in the end. Nobody teaches that lol...

[@meghasharma1962]

Hey, does it require linux or we can do in windows?

[@surplusvalue3271]

same!

[@surplusvalue3271]

@@meghasharma1962 maybe use WSL, though i don't know how are dirs organized in wsl

[@gaomingt]

22:40 Also, if you don't have write permission on a file but have write permission on its directory, you can still delete the file.

[@steveroger4570]

This is better than my entire degree in my uni

[@mubintirsaiwala7141]

I just can't thank you enough. Great content.

[@MubashirullahD]

This entire talk is this smart telling you you don't know things. :)

[@venusumanthpotru9535]

This is super helpful 👍. Thanks a lot for uploading it to KZbin.

[@sefacorleone8276]

oouuww yes.. i will put that knowledge inside my head. Thank you!

[@keonys1]

Very insightful! thank you for releasing to us

[@priteshugrankar6815]

This is truly amazing!! Thanks for sharing!! By the way, I see vendor Perl and core perl in the path at 11:40. Does it mean the instructor is using Perl? If so, for what purpose?

[@harishkrish14386]

Thanks fr these videos which have released! ❣️

[@kortaffel]

40:30 you don't need to "sudo su". A simple "su" is suffice. "su -" if you want to get rid of enviroment variables and a login shell

[@MichaelS-em8id]

Are there solutions for the exercises given? I'm having trouble with Question 3. Is it telling me to execute the file with *ls semester*?

[@hulk94smash]

WOWOWOWOWOWOW THIS IS GOLDDD!!! 🔥💯 wish I knew this year's ago 😭

[@mcvgs1780]

I wish I had these kind of lectures in college.

[@beingchaitali]

Really great lecturer , very helpful . Is there any way to get exercise example ?

[@mukulkumar2316]

this is exactly what i needed

[@advitiayanand5974]

That's basic? Man I'm hyped!

[@je9625]

Is there an example of screen casting from the command line he refers to ?

[@FrederizEguren]

He is very eloquent.

[@clanoftheducks1850]

You probably want to explain su stands for substitute user not super user, which is a common misconception even in the Linux world, but su let's you go into a shell for another user, not just the superuser, hence the name.

[@iduran]

Nice terminal setup. I already checked the instructor's dotfiles but couldn't find which font he is using. Any idea what font that is?

[@santiagotodisco2668]

CTRL + L for cleaning and cd - for moving back and forward? Totally worth the time to see the lecture. I'm going to see all of them

[@fhajji]

Same: I didn't know about 'cd -'. Always been using pushd and popd. Ctrl-L I knew about from Emacs. :)

[@kwangee]

About the "echo 1060 | sudo tee brightness" command 42:17 , does this mean if we somehow run a malicious .sh script obtain from internet that contain similar command but does malicious action, it will execute successfully? since this command does not require shell login as superuser

[@DutchmanDavid]

`which` and `where` were important for me that one time I tried to (roughly) time a short piece of bash script. For some reason `time` did *not* want to accept some parameters I gave it. Turns out I was using the `shell reserved word`, not the *time* program that also exists in `/usr/bin/`. Executing the next gave me info on why my script didn't work: > which time time: shell reserved word > where time time: shell reserved word /usr/bin/time This showed me I just needed to add /usr/bin/ in front of the command to fix my troubles.

[@maksimbronsky7117]

On Windows the adequate command for xdg-open is simply explorer.exe :-)

[@ramprax]

You can use 'start ' instead of explorer.exe

[@chococandy8009]

Probably the only semester that I would like to attend without bunking a single lecture ;) It was fun.

[@stardusts42]

FYI, you can drag and move the subtitle from the bottom to other places until the instructor types "Ctrl + L"

[@shawnxihaowu7638]

Thank you for this lecture!

[@rajasekharreddy7977]

Very insightful and useful lecture.

[@warshipwarriors]

Nice lectures, happy to learn more

[@tetomdq]

# to run command as root. * head explodes * Doing my first steps on Debian Thank you, thank you, thank you for these lectures!

[@muddi900]

This is my reference book now.

[@Sethsm1]

Extremely helpful. Thank you.

[@kellybmackenzie]

This is awesome, thank you so much!

[@edgrimm5862]

Most of the stuff under /sys/class/ are indirect links to the directories that have the actual stuff. By default, find does not follow symlinks. If you search from /sys/, you'll probably find brightness under kernel, devices, and modules.

[@perlaramos8783]

I wish I had this course at my university!!!

[@expeditiontoabyss3597]

this is crazy good, thanks

[@angelsalinas9697]

can someone help me, when I do, cd /sys in my mac terminal it says no file or directory found.

[@narindersharma303]

Very nicely explained!

[@adjusted-bunny]

How can you run "tee" as root (sudo) because it is not an ordinary program but a shell utility like ls? In my logic you would need a root shell, too. I'm confused.

[@akashpatil7662]

Thank you these lectures

[@euriskoo]

8:03, Actually the program doesn't treat the string as one argument, it same as using double quotes, it's still an array of arguments.

[@user-ue7zt5pt8o]

wow, that 's cool!Thank you :)