Linux commands for day to day use

file search

1. print top lines

head sample.log

head -n 20 /path/to/logfile.log

2. print bottom lines

   tail  sample.log

   

terminal commands

control A - begining of the line

control E - end of the line

control right arrow

control left arrow

control U start line delete

control K start from custor delete 

file system

cd 

when folder name has space

cd Exercise Files error

cd Exercise\ Files

ls -R inside directory

ls --color=always

rm -sample?.txt

vs

cat sample.txt | cat -n | tail -n4

grep "hello" sample.txt - simple search

grep -in "hello" sample.txt - with line numbers /ignore case with line numbres

grep -vi "hello" sample.txt - with line numbers /ignore matching case and print remaining

grep -n "hello" sample.txt - with line numbers

grep -E "[hijk]" sample.txt - search for letters and shows the results

grep -E "/w{6,}" sample.txt - count words and shows the results

log analysis with awk command

awk '/error/ {print}' /var/log/syslog

awk '{print $2}' sample.txt

awk '{print $2 "\t" $1}' sample.txt | sort -n  more filter on tablular data 

sed s/Orange/Red/ sample_data  to edit& replace text

s for substitute

g for global replace

sort sample.txt

sort -k2 -n sample.txt sort the data

sort -u sample.txt - remove dublicates only unique print

rev tac tr

tar -xvf log.tar.gz 

log analysis

less filename

cat filename | grep "string" | awk '{print $9}' |sort -u > users.txt

free -h

cat /proc/cpuinfo - c

df -h memory information 

copy the text from ssh editor to local 

cntrl+insert for copy

shift +insert for paste

grep commands for daily use

 grep -B 3 -A 2 'Invalid user' /var/log/auth.log

https://www.loggly.com/ultimate-guide/troubleshooting-with-linux-logs/

https://www.loggly.com/ultimate-guide/troubleshooting-with-linux-logs/

grep -l phoenix *

refer the link https://phoenixnap.com/kb/grep-command-linux-unix-examples

scp command to transfer files

for more refer this link https://www.youtube.com/watch?v=fmMg6cyww14

1. search text in vi editor

1. Press ESC key.
2. Type /vivek.
3. Hit n to search forwards for the next occurrence of word named “vivek”. You can press N to search backwards.

Find Files linux commad

find / -name "*conf" 
find /home/exampleuser/ -name "*conf" 

2. How to unpack (ungzip, unarchive) a tar.gz file

For many systems, REBOL is distributed as a tar gz file. This is a common archive format. Here's how to unpack it...

For tar.gz

To unpack a tar.gz file, you can use the tar command from the shell. Here's an example:

tar -xzf rebol.tar.gz

The result will be a new directory containing the files.

(Also, on many systems, when you download the tar.gz from a web browser, an unpacker will open, and you can just use that.)

For just .gz (.gzip)

In some cases the file is just a gzip format, not tar. Then you can use:

gunzip rebol.gz

In order to execute it, you will need to add execute permissions to the file:

chmod +x rebol

for more refer below videos on detailed commands