command-desc

Command Descriptions -

#!/bin/bash - sheebang where bash is executable
then always give metadata before start writing into the files
touch - creates a file
vi/vim - create + open up the file
why touch & vi - touch uses in automation purpose generally where we have to create 1000s of file
write inside a file - esc -> press "i" -> start writing -> esc -> wq! (save & exit)
chmod - grant permissions
ch - change
777: all permissions
4: read, 2: write, 1: execute
root-user which-grp what-are-your-perm
man - mannual cmd that shows detail of it, use it as a suffix, eg; man ls
pwd - present-working-directory
mkdir - create/make directory/folder
cd - change directory
cat - concatenate and display files
df -h - disk space, human readable
free - memory of the machine
nproc- cpu of the current machine
top - every detail like, current running process, tasks running at the moment, sleeping process, cpu, m/m, node status
set -x - print the command then execute the command ie, prints in debug mode
ps -ef - ps: process, ef: entire process in full format
grep - global regular expression print, it allows us to search some text
pipe | - sends the output of the first command to the second command
awk - pattern scanning & processing lang. Filter out the info from the o/p
set -e - exit the script when there is an error
set -o - pipefail
curl - retrieve the info from the internet
wget - download the file from internet
sudo - substitute user do, switch to root user, super user
su - switch user
p - parent
nslookup - checks the ip add
netstat - ports that are listening
> - overwrite
>> - append
alias - eg; alias gpom="git push origin main"
R - copy dir with the whole subtree
tr - translate eg; cat fil1.txt | tr a-z A-Z > upr.txt
find - finds the file by specifying the name of it
trap - traps the signal and perform the executions on your behalf eg syntax; trap "echo don't use the ctl+c" SIGINT