Terminal Commands

Popular commands brief for a fast access

By Rogie

FLAGS

*  match the pattern 
~  telda
|  pipe
r  recursivly
w  write
f  force
i  bang
v  print log

Terminal tips

tab hit to auto complete
reset resets all terminal default look & others
clear clean terminal window & you can scroll for old writings
Ctrl+L clean terminal window & you can scroll for old writings
!x repeats the most recent command starting with x
history grape all the commands you wrote entirely the history of the bash shell
man X show you the manual of command ”X”
echo “word”  print “word” on the screen
echo “word” > name   put “word” in a new file called name
echo “word” >> name   adds “word” + previous words into file called name
./mario < inputFile   takes data from inputFile to use it as input into mario file
history | grep ls takes all the history outputs & feeding it to grep command so that grep recognizes the ls words in it
cat fileName looks inside that filename, Prints current file contents to stdout
;  semi colon allow us to run many programs in same line, Just divide between them by a semi colon
which commandName check if you have a program installed that uses that commandName

COMMANDS

Files & Directories

• list

ls list the folders & files in this directory
ls -l list files + more info + permissions
ls -a list the folders + Hidden
ls -la list the folders + Hidden + Permissions

• cd change directory

cd location change directory
cd ~/location go back till this location directory
cd .. up one level location
cd .  takes me to the current Directory
cd -  takes me to the last Directory I was in before the current
cd ../directory1/directory2/ takes you to directory2 that's inside directory1
pwf show you the current directory location details

• cut & copy , create files & directories

mv fileName newFilename rename file
mv anyFile anyFolder anyFile lastFolder moves everything in the lastFolder
cp oldFile.c newFile.c copy the oldFile & name the newFile
touch filename create a new emty filename
mkdir Name     makes a new directory(folder) called Name
rmdir Name     remove the directory if only it's empty

• delete, remove files & directories

rm file.c      remove the file with ask you first (only files)
rm -f file.c   -f flag forces removing file without Asking
rm -r Name     remove the directory
rm -rf Name    remove the directory & all it's files + f without   Asking
rm *1  remove the files & directories with pattern 1 in it's name
rm *   remove all the contents of the current directory
rm -i  -i flag requires user’s confirmation
DANGEROUS: don't do it
rm -rf ~   removes everything in home directory
rm -rf /   removes everything in root directory

search & find words, files, directories

• grep

grep “wanted word”    recognizes wanted word while typing
grep “wanted word” X  search for “wanted word” in X Location, files
grep “wanted word” *  search for “wanted word” in all files &folders
grep -r               search in directories & sub-directory

• find

find . -name “cat”  search for folder or file with the exact name “cat”
find . -name “*cat” search for folder or file with after pattern name “cat”
find . -name “cat*” search for folder or file with after pattern name “cat”
find . -name *.c    search for folder or file with .c extenction
find . -type d      search for all directories in the current directory
find . -type f      search for all files in the current directory

Text Editors

• gedit & nano

gedit opens gedit & you can't use Terminal till you close Gedit
gedit name.txt opens gedit & make file called name
nano opens a bacic text Terminal Editor
nano filename opens filename in nano texteditor
ALT+L turn off text-wrapping

• vim, vim commands

vim filename opens filename in cim rich texteditor
vi filename  opens filename in cim rich texteditor

*PIPES*

• redirect.c

int main()
{
string input = GetString();
printf("%s\n", input);
}

• stdout standard output

./redirect  > file.txt
saves the output to the file.txt & replace evetthing in file.txt
./redirect >> file.txt
Append (Adds) the output to the current contents in file.txt
2> 
prints only error messages
./redirect > /dev/null
output will be discarded, Data Black hole

• stdin standard input

./redirect < file.txt > file2.txt 
Get the input from file.txt & saves the output to the file2.txt & replace everything in file2.txt
Notice
We only have 1 GetString in redirect.c so it will take only 1 line input

Output of a program to Input of another program

• hello.c

int main()
{
printf("Hello World\n");
}

• command

./hello > input.txt
Take hello output into input.txt
./redirect < input.txt
Take input.txt as an Input
./hello > input.txt; ./redirect <input.txt
same result of the first two just using one line

Output of a program on the “Pipe Left” to Input of another program on “Pipe Right”

• pipeline

To avoid creating that extra file "input.txt" from previous example
./hello | ./redirect
same result as previous just using pipe

Combine Command lines using Pipeline

wc -l     
-l flag to count lines, wc to count
ls | wc -l
combining ls command as stout to show the current files in directory,
then use this result as stdin to ws -l to count the words,
So we know how many files in this directory
cat students.txt | sort
Will get the stdin from cat and stdout to sort, result show them in alphabetical order
cat students.txt | sort | uniq  > final.txt
Saves all sorted without duplication names in final.txt
sort < students.txt | uniq > final2.txt
same result

Extras

operators

|     or   0|0= 0, 0|1 = 1
^     exclusively different or    0^0= 0, 0^1 = 1
~     telda flipping operator from 0 to 1, 1 to 0
&     And 0&0 = 0 , 1&0 = 0
<< :  shift operator  1<<7 = 10000000

echo

echo $?
Echoes (prints) the exit value for the previous command.
If it failed it will be different than zero (0).

$ cd ~
$ echo $?
> 0
$ cd //whatever/
> bash: cd: //whatever/: No such file or directory
$ echo $?
> 1

make file, More details

clang file.c
compile the file in c language, clang is a very basic c language compiler
clang -ggdb3 -O0 -std=c99 -Wall -Werror soso.c  -lm -o soso
full clang = make
make file
compile the file with all the clang flags