notes/session-14.txt at main · daws-88s/notes · GitHub

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inode symlink hardlink

inode = stores metadata of the file/directory

file type -> file/directory/link
Owner group
Permissions
size
create, update, etc
actual memory block address

inode does not store actual file content

symlink == shortlink == softlink
1. short cut to the file/folder
2. inode number is different for symlink
3. if actual file is removed, then symlink will break
4. uses for backward compatability, switching versions and rollback is easy
5. You can create symlink for folders and files also
6. You can create symlink across different filesystem

YUM -> Before RHEL-8 YUM is the package manager
RHEL-8 DNF is the package manager

app-3
app-4

/var/lib/jenkins -> jenkins-2.8

jenkins-2.9

/var/lib/jenkins -> jenkins-2.9

Hardlink
=========
1. You can't create hardlink in another filesystem
2. Hardlink is same as original file but can be different name
3. hardlink inode numbers are same
4. they points to same memory location, so memory is not wasted
5. you can't create hardlink to folders
6. hardlinks are used for backup.
7. when all links are deleted, then only file will be deleted.

using inode number and find command within the same FS

1. time taking
2. human errors
3. everytime from the scratch
4. can't rely
5. if scale is increased manual way is not possible

scripting
===========
commands in a file and run it called scripting

where to store scripts?
===========
git -> vcs

1. version control
2. who did the changes, when did the changes
3. you can track who did the changes
4. restoring is easy
5. review is also easy -> Pull Requests
6. secure place to store the code

centralised vs distributed
===========================
SVN -> sub version control

10 files
9 files
staging/temp area -> add 9 files to staging area
then commit to local repo

1. clone the repo -> first time download

main/master is the default branch

#!/bin/bash -> shebang

shebang is the interpreter of the code in shell script that checks and compiles for errors

bash scripting == shell scripting

2. add files to staging area

git add <file-name>

git config --global user.email "info@joindevops.com"
git config --global user.name "Sivakumar Reddy M"

3. commit to local repo

git commit -m "hello world completed"

git push origin main

don't edit files inside linux server...

tomorrow's session
==================
variables
data types
conditions
loops
functions
error handling

OOPS