| Command | Description |
| # | root user prompt |
| $ | user working prompt |
| $logname | Displays current user name |
| $pwd | Present working directory |
| $date | Display current date & time |
| $cal | Display current month calendar |
| $cal 2022 | Particular year total months |
| $cal 02 2022 | 2022 year 02nd month calendar |
| $who | To display the information about all the users who have logged into the system |
| $whoami | It display current user name |
| $finger | It displays complete information about all the users who are logged in |
| $uptime | How long server up & running, how many users connected and load avg time |
| $which or $whereis | Given command location Example: which date |
| $tty | Terminal position |
| $df | Display disk free size |
| $du | Disk usage information |
| $clear | To clear the screen |
Creating Files
cat (concatenate): It is used to create a file and display, appending the contents of the file.
To create a file:
$cat > filename
Welcome to Webnoid
ctrl + d (To save the file)
To display the content of the file:
$cat filename
To append the data in the existing file:
$cat >> filename
Webnoidschools
ctrl+d (To save)
Touch: It create multiple files but all are empty.
Syntax: $touch file1 file2 file3 ……. filen
Example:
$touch file1 file2 file3
ls: Display the contents of a directory.
Syntax:
$ls [options]
Options:
-r -> Reverse
-a -> hidden
-R -> Recursively
-i -> inode
-l -> lode list
-h -> human readable
mkdir: Created a directory.
Syntax:
mkdir <Dirname>
$mkdir Linux
To create multiple directories:
$mkdir Dir1 Dir2 Dir3 ................... Dirr
To create a Nested directory:
$mkdir -p world/Asia/India/Telangana/Hyderabad
p is parent
To check:
$tree world
or
$ls -R
Navigation Commands: (cd -Change Directory)
| Command | Description |
| cd /home/webnoid | Changes current location to destination location |
| cd .. | To go one level back |
| cd ../.. | To go two levels back |
| cd | To change user’s home directory |
Example:
$cd world
$ls
Note: The trailing slash (/) is optional when your are using the cd command. It indicates that the name being specified is a directory.
Example:
$cd Documents/
cp: Copies files or directories from one location to another.
Syntax:
cp [options] source Destination
-R -> Copies recursively
-f -> Copies Forcefully
-v -> Provides verbose output
Examples:
Copies one file to another:
$cp file1 file2
Copies multiple files into Directory:
$cp file1 file2 Documents
Copies one directory to another:
$cp -R Documents unix
$cp -rvf Documents unix World/Asia/India/Telangana/Hyderabad
$cp /var/log/messages .
mv: Moves or renames files and directories.
Syntax:
mv [options] SOURCE DEST
Options: -v -> verbose
Rename the file by specifying the file name & new name of the file:
$mv messages messages.bak
Move it to the test directory for safekeeping:
$mv messages.bak test/
$ls test
rm: Deletes files or directories.
Syntax:
rm [options] FILE
Options:
-i -> Interactive
-r -> Recursively
-f -> Forcefully
Delete the messages.bak file:
$cd test
$rm -i messages.bak
Delete the test directory:
$cd ..
$rm -rf test/
file: Displays the type of a file
Syntax:
file <filename>
Example:
$file test1
test1 : Empty
$file /etc/passwd
passwd : ASCII test
Meta Characters or Wild Card Characters
a) * : It matches zero or more characters in the given file.
Examples:
Displaying file start with ‘a’.
$ls a*
Starts with t and end with g
$ls t * g
Listout end with g only
$ls *g
Removes starts with t
$rm t*
Removes end with g only
$rs *g
Copies start with a
$cp a* Documents/
$co -rf t*g Documents/
Copies current directory all files
$cp -ruf * /backup
b) ? : It matches any single character in the given file.
Example:
Display single character files.
$ls ?
Display two character files
$ls ??
List four character files but first one is ‘a’.
$ls a???
Removes two character files.
$rm ??
Copies three character files.
$cp ???
c) [ ]: It matches any single characters in the given list
Example:
Displays given matching character files.
$ls [a e i o u]
Displays start with a, e, i, o, u files.
$ls [a e i o u]*
Removing start with a, e, i, o, u
$rm [a e i o u]*
Copying start with a, e, i, o, u
$cp [a e i o u]* unix/
d) [-] : It matches any single characters in the given range.
Example:
Displays starts with a, b, c, d, e, f, g
$ls [a-g] *
Display start with a-e & p-v
$ls [a-e, p-v] *
Removes a-e
$rm [a-e] *
Copying files a-e & 0-9
$cp [a-e, 0-9] * unix/