echo is a command that outputs the strings it is being passed as arguments
echo 'Hello World'
Hello World
wc - word count
echo 'Hello World' | wc
1 2 12
alias set an alias
alias gp = 'git push origin master'
grep used for regular expression
seq 30 | grep 3
3
13
23
30
Or
seq 30 | grep 3 | wc -l
4
Creating a new file using > operator
Append for existing fill using the >> operator
echo -n "Hello" > hello-world.txt
echo " World" >> hello-world.txt
cat print the conent of a file
cat hello-world.txt | wc -w
Move a file for a different directory with the mv command
mv hello-world.txt ~/Downloads
cp command for copy a file
The man provides the command documentation
man cat
To show only the first 20 lines:
man cat | head -n 20
Similarly, the help command returns the help documentation of the command (not always the man is available)
help cd | head -n 20
init commit