1. Command line

2. Folder structure Only a partial list of the default folders are shown
2018
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3. Terminal GUI is nice to have CLI is a must It’s intuitive (sometimes)
It’s user-friendly (sometimes)
Multitasking is easy
It doesn’t scare people away
CLI is a must
Fast
Powerful
Feature-rich
Complicated
Often the only way
Only way – professional tools, developer tools, remote access to servers, network devices management, fixing broken things
2018
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4. The basics* You’re shown the current working directory
Tab autocompletes (program names, file names, some commands)
Up/down arrows go through previous commands
Ctrl + c will (most of the time) abort/exit the current action
Ctrl + d sends end of file signal
Ctrl + l will clear the screen
Widely-accepted practices, work on most terminals
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5. Basic commands ls list directory contents cp copy file mv move file
ls -l list directory with details
ls -la list directory with details, show hidden files
ls -lat list directory with details, show hidden files, order by time modified
cp copy file
mv move file
rm remove file
mkdir create directory
rmdir remove directory
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6. Navigating in directories
cd foldername move to a folder
cd move to the parent folder
cd ~ move to the home folder
cd / move to the root folder
cd ~/P/subjects/prog1 move to the folder specified (full path)
cd ../.. move two folders up (relative path)
cd ../Desktop move one folder up and then to Desktop (relative path)
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7. Man pages
man pow
man cp
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8. Viewing files cat filename less filename more filename head filename
cat -n filename
less filename
more filename
head filename
tail filename
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9. Running programs Programs in the PATH can be run just by name
env list your environment, including PATH
To run your own programs, you need to specify the path to it (either relative or full)
./myprog program in the same directory as current path
../myprog program in the parent directory
/home/usr/Desktop/myprog program full path
To run a program, you must have execute privileges to it
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10. Privileges Each file has a set of privileges for
Owner
Group
All other users
Most common privilege types: read, write, execute (rwx)
ls -l to view privileges
chmod to modify privileges
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11. Compiling gcc the program -o filename set the output file name Flags
-Wall Show “all” warnings
-Wextra Show additional warnings
-Wconversion Show type conversion issues
Etc
gcc -o myprogram -Wall -Wextra -Wconversion mycode.c
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12. Try it out Optional: download basic vim config file:
Go to home dir: cd ~
Download config: wget blue.pri.ee/ttu/files/.vimrc
Start to write a code file vim mycode.c
Press the letter i to enter insert mode
Code hello world
Press escape to exit insert mode
Save and quit vim !?!?!
Compile from command line
Execute from command line
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13. Let’s talk streams Three standard streams: stdin, stdout, stderr
The streams can be redirected from their default locations
No need to change the code, works on OS level (win, linux, mac)
Allows us to test our (any) programs
Easier to store the output of any terminal program
image: wikipedia
2018
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14. Redirecting input stream (stdin)
Typically the program gets input from the keyboard
We can redirect this input so it would come from a file
Linux: ./program < data_file
Windows command prompt: program.exe < data_file.txt
Windows Powershell: Get-Content data_file | ./program.exe
Data file is just a normal plain text file!
MS Word, Wordpad, Openoffice Writer etc don’t produce normal text files
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15. Redirecting output stream (stdout)
Used to store the output of the program to a file
The text will no longer be shown on the screen
Linux: ./program > data_file
Windows: program.exe > data_file.txt
Both streams can be redirected at the same time ./program < input_data_file > output_data_file
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16. Lab task #1
Take the code from last week (matrices) and use stream redirection on it. If necessary, change the code to accommodate it
Sample input and expected output are given under lab materials
Make sure the answers are correct
Redirect both stdin and stdout (input and output) – this means your input data comes from a file and the result is written to another one
Demonstrate it
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17. Lab task #2 Create a program that could verify dates
Use this program with the stream redirection for testing
Don’t forget to test the edge cases (e.g. leap year 29th Feb)
The task description, test data, advanced additions and guide are posted on the website
Use the UML as the basis for your code
Do not forget to compile after each update!
Reminders and examples on logic operators on the following slides
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18. Logical operations Logical and, conjunction Logical or, disjunction
Logical negation, inversin A B
A &&B F T A B
A || B F T A !A F T
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19. Examples if (day >= 1 && day <= 29 && leapYear)
if (sorted == 0)
if (!sorted)
if (input >= MIN && input <= MAX)
if (input < MIN || input > MAX)
if ((input >= MIN && input <= MAX) ||(ignoreLim == 1))
if (day >= 1 && day <= 29 && leapYear)
if (month == 1 || month == 3 || month == 5)
2018
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