Unix is an operating system which was first developed in 1960. It is astable, multitasking, multiuser operating system for all laptops, desktops and servers.
There are three parts of an UNIX operating system.
1. Kernel - The hub of the os. It manage time and memory. Handle file storage and communication.
2. Shell - It works as a inteface between user and the system.
ls - list the content in a directory
(type "man ls" to get more details about ls command)
cd - change the directory
cd .. - goto parent
cd or cd ~ - goto home
pwd - view the path to the current directory
mkdir - make a new file
rmddir - delete a directory if it is empty
cp - copy file
useage:"cp file1 file2" this will copy file1 as file2.
rm - remove file
cat - concatinate
useage: "cat foo.t" display the content of foo.t
("cat > bar.t" "cat >> bar" & "cat < bar.t")
less - view page by page
head - view first lines in a document
useage: head 5 foo.t - will view fist 5 lines
tail - view last lines in a document
useage: tail 5 bar.t - will view last 5 lines
wc : count words in a file & will give the output as "lines words charactors"
grep - find keywords in a file
useage: "grep 'foo bar' text.t" search for the pattern "foo bar".
"command" > file - redirect the output to file
"command" < file - redirect the input from file
command1 | command2 - pipe command1s output to command2s input
man "command" - read the manual of the command
chmod - change the file mode
"command" & - command will run in background