ls -lhS

ls -a

ls -A
dos not show shortcut directories

linux default
rm = rm -i

mkdir foldername
rmdir -f foldername
rmdir emtydir

touch filename
create and if file exist change timestamp

gerp "serchterm" filename

case insensetive
gerp -i "serchterm" filename

all line except thos contain search term
gerp -v "searchterm" filename

number of eccurance
gerp -c "serchterm" filename

find directory -name "*.txt"
find directory -size +10M

Menue Options

Open a cron jobs file with ctontab-e and
add the following line to enable daily backups:
$ crontab -e # open crontab file
@daily rsync -aze ssh ubuntu@10.0.2.50:/home/ubuntu/sampledir
/var/backup
In the preceding example, we have used a pull operation, where we are downloading files from
the remote server. Rsync can be used to upload files as well. Use the following command to
push files to the remote server:
$ rsync -azP -e ssh backup
ubuntu@10.0.2.50:/home/ubuntu/sampledir
#linux
#rscnc

Rsync provides tons of command line options. Some options that are used in the
preceding example are –a, a combination of various other flags and stands for achieve.
This option enables recursive synchronization and preserves modification time, symbolic
links, users, and group permissions. Option -z is used to enable compression while
transferring files, while option -P enables progress reports and the resumption of
interrupted downloads by saving partial files.
We have used one more option, -e, which specifies which remote shell to be used
while downloading files.
#rscnc

Rsync is a great tool to quickly synchronize the files between source and destination,
but it does not provide bidirectional synchronization. It means the changes are synchronized
from source to destination and not vice versa. If you need bi-directional synchronization,
you can use another utility, Unison.
#Unison

If you wish to have your own Dropbox-like mirroring tool which continuously monitors for local
file changes and quickly replicates them to network storage, then you can use Lsyncd.
#Lsyncd

Network File System (NFS) is a distributed filesystem protocol that allows clients to access
remote files and directories as if they are available on the local system. This allows client
systems to leverage large centrally shared storage. Users can access the same data from
any system across the network. A typical setup for NFS includes a server that runs the NFS
daemon, nfsd, and lists (export) files and directories to be shared
#NFS

daemon : a process that run in backgroun (to provide networkbase functionality)

/bin/systemctl

initctl
systmctl

interface(phyiscal,VLAN,bridge)
ip link list
ip link list lo
//for down a link
ip link interfacename dow
//assigning an ip to an interface

ubunto