Linux intro

Enable windows:

windows - start - features - turn windows fratures on or off

on - virtual machine platform
on - windows subsystem for linux

Restart

window's CLI commends :

wsl --install - i Ubuntu

usname - Ubuntu
passw - ubuntu Default

pwd - /home/ubuntu - home path/username

path - username rendum serinthu dhan home.

uname -a os version

whoami - username

clear CLI :

clear
ctrl+L

history - commends history

mkdir Dummy - create folder
mkdir -p dir1/dir2/dir3 - sup folders

vi Editor :

vi sample.txt

i -insert mood
Escape
:wq - save/quit
:q - quit
:q! - not save
dd - delete
ctrl+ shift + c -copy
ctrl+ shift + v - paste
press d two times helloworld - delete line

sudo apt-get install vim - updrade vim

vim Editor:

vim sample.txt

i - insert
enter - next line
Escape
:wq - save/quit
:q - quit
:q! - not save
: set number - 1 a 2 b 3c
/git - search word

nano Editor :

ctrl + x - save
y - yes
ctrl + x Exit

touch sample.txt - create file

rm sample.txt - remove file
rm txt - remove .txt files
rm - delete all files

ls txt - list .txt files
ls he - list start file name like he

cat sample.txt view content
cat sample.txt >> s1 copy file - append
cat/home/ubuntu/data.log - absl path

cp sample.txt s1.txt old file / copy file

mv sample.txt s1 rename file/ rename
mv .sl hidden file
mv .s1 s1 remove hidden

echo "Hello world " print cli

echo "Hello world " >>sample.txt create file or append mention file

history >> history.txt create file cp commends

ls - list files,file,dir
ls -l long list
ls -a - hidden files and dir
ls -s -sort
ls -r - reverse order
ls -t - time
ls *py - list emd match files
ls file - list start match file
ls

ls -lstr

ls .py - select .py file
ls time - start file

cd - current dir home
cd . - current dir
cd .. last dir
cd ~ home dir
cd - previous dir
cd ../.. - 2 dir back vara

vi .bashrc
source .bashrc - file execute

.bashrc - set Environment variables or program home

set program files home next execute .bashrc file

important:

hard link and soft link

hard link :
ln original.txt hard.txt

soft link :

ln -s original.txt soft.txt

alias p="pwd" short cut

schedule tasks:

2 clicks code run

monitoring live logs:

three type monitoring

top - task manager
ps
ps -aux - runining files

ps -aux | grep data_preocessing.py - particular file

ctrl + z -exit

cat data_process.log - viwe list log

tail -f data_process show live log
tail -10 data_process show live log last 10 lines

kill -9 168858 - force kill

particular file log

download links files images :
wget "http://img" - download

Disk:

df -h Disk free space
du -sh scripts file Disk usage

free -m free memory

free -g ram usages

remove cache :

sudo sh —c "sync; echo 3 >/proc/sys/vm/drop_caches"

zip and tar :

zip f1.zip scripts zip new folder name/zip folder

zip -r f1.zip scripts

ls -lstr | tail -f

unzip f1.zip

tar:

tar -czvf sample.tar scripts/

compress
z - tar type files force
details
verbose - list files
following list

untar :

tar -zxvf sample.tar scripts/

x -extract
z - tar type files force
details
verbose - list files
following list

word count :

wc -w sample.txt - words

wc -l sample.txt - lines

wc -c sample.txt - characters count

order :
sort file1
sort -r file1

sort numbers :

sort -n file1

head :

head sample.txt 1st 10 lines

head -n 5 sample.txt

tail :

tail sample.txt last 10 lines

tail -n 5 sample.txt

grep : search

grep ERROR log1.txt list matching lines
grep -i error log1.txt list -i upper or lower matching lines
grep -v error log1.txt ignore error and list other ines

grep WARRING *.txt global search

grep WARRING *.txt | tail -f

Network commends :

SSH - same network laa connect aa irukka ..en lap friend laptop connect pannalam

SCP - company server oda connrct panna .. ip add ,passw set pani work pannanum server laa

ifconfig - ip address

ssh :

ssh anoter way

2.30
tools:

putty ssh
winscp scp

find :

find . -name log.txt
find . -name ".txt"
find . —type f —size +10M 10mb mela
find . —mtime -1 1 day modification files
find . -empty
find . -name ".tmp" -delete

awk

group management

chomd 777 dummy -files

chomd -R 777 dummy -directory's

scheduling :

crontab -e

crontab formula:

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crontab stands for "cron table". It's a file where you define tasks to run automatically at a set time or date.

🔁 Cron = scheduler
📄 Crontab = list of scheduled tasks

🔧 Basic Crontab Command

Command Description
crontab -e Edit your crontab file
crontab -l List current cron jobs
crontab -r Remove all cron jobs
crontab -u username -l View cron for another user (root only)

Crontab Syntax

• * * * * command_to_run | | | | | | | | | └──── Day of the week (0 - 6) [Sun=0] | | | └─────── Month (1 - 12) | | └────────── Day of the month (1 - 31) | └───────────── Hour (0 - 23) └──────────────── Minute (0 - 59)

📅 Common Examples

Time Crontab Syntax Description
Every minute * * * * * Runs every minute
Every hour 0 * * * * Runs at minute 0 of every hour
Daily at 5am 0 5 * * * Runs at 5:00 AM every day
Every Monday at 3pm 0 15 * * 1 Runs at 3:00 PM on Mondays
On Jan 1st at midnight 0 0 1 1 * New Year execution

• * * * * echo "Hello from cron!" >> /home/user/cronlog.txt

corntab guru website

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