List of basic commands of unix
reboot
- Immediately stops all running processes,
shuts down the system, then reboots.
sudo - Runs commands as root, which means no limitations due to permissions.
shutdown
- Stops all running processes and shuts down
the system.
Parameters can be specified to issue a delayed shutdown or a
shutdown at a particular time.
date
- Prints out the current system date and
time.
Specified parameters can change the format of the output.
df - Reports the disk space usage for the file system.
hostname
- Displays the name of the current host
system.
ps - Displays information about all of the processes currently running on
the system.
du - Disk usage
ps - List running processes
To know
the process id of a process running
ps -elf | grep process_name
ps -fA | grep process_name
| ->
pipe character is very useful for redirecting output of one command to other
grep is used to find the pattern
To create
a file
cat
filename
touch
filename
To search
something in a file
grep -i
thing_to_be_searched filename
To search
something across directories
grep -rn
pattern_to_be_searched directory_starting_from_where_search_to_be_started
To view
processes along with the memory they are consuming run
top
Ctrl + M will sort in decreasing order of
memory consumption
chmod / chown - Changes the access permissions of one or more files (chmod) or
changes the ownership of a particular file to a new user (chown).
Only users with permission or ownership of a file can change that
file’s permissions or ownership.
chown owner_name filename
chmod 755 filename
Here 7 is
the permission for owner
5 and 5
for group and others respectively
7 - xrw
5 - xr
2-r
4-x
1-w
Access permissions are of three
types
x Execute permissions (4)
r Read permission (2)
w write permissions (1)
Aur linux has concept of owner,
group and others.
Owner is the owner of the file
Every file or directory belong to
a group
And third is others(not owner and
not belonging to the group of the file)
Permissions are in the order
Owner permissions Group permissions
others permissions
