Added README.md file instead of the TXT file

Linux/SUID/README.md

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+## SUIDs, SGIDs, and Sticky Bits
+
+In Linux, file permissions are given in 3 categories: owner, group, and other users. And on top of that, special permissions like SUID, SGID, and Sticky Bits are given to those categories respectively. 
+
+**SUID** -> `Set User ID` -> Helps running a program as another user than the one executing it 
+**SGID** -> `Set Group ID` -> Helps running a program as another group permission than the one the user executing it is a part of. 
+**Sticky Bits** -> Used to set delete permissions over a directory. Only file owner, directory owner or root can delete it. 
+
+For setting SUID, SGID, and Sticky bits, there are numeric notations: 
+
+SUID -> 4 -> u+s 
+SGID -> 2 -> g+s 
+Sticky bit -> 1 -> o+t 
+
+- SUID is set on owner. It can't be set on other 2 categories. 
+- SGID is set on group. It can't be set on other 2 categories. 
+- Sticky is set on others. It can't be set on other 2 categories. 
+
+chmod 4222 filename 
+4 -> SUID
+222 -> Respective file permissions for the 3 categories. 
+
+## Using with chmod
+chmod u+s filename  -> Used to set SUID over a binary file 
+chmod g+s filename  -> Used to set SGID over a binary file 
+chmod o+t filename  -> Used to set sticky bits over a directory 
+
+-rwsr--r-- : s bit is for SUID set bit + having executable file permission (x). 
+-rwSr--r-- : S bit is for SUID set bit and no executable file permission. 
+-rw-r-sr-- : s bit is for SGID set bit + having executable file permission (x). 
+-rw-r-Sr-- : S bit is for SGID set bit and no executable file permission. 
+-rw-r--r-T : T bit is for Sticky bit 

Linux/etc-passwd/README.md

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+# /etc/passwd file
+```bash
+sabyasachi@h0tPlug1n:~$ cat /etc/passwd 
+
+root:x:0:0:root:/root:/bin/bash 
+daemon:x:1:1:daemon:/usr/sbin:/usr/sbin/nologin 
+bin:x:2:2:bin:/bin:/usr/sbin/nologin 
+sys:x:3:3:sys:/dev:/usr/sbin/nologin 
+sync:x:4:65534:sync:/bin:/bin/sync 
+games:x:5:60:games:/usr/games:/usr/sbin/nologin 
+man:x:6:12:man:/var/cache/man:/usr/sbin/nologin 
+... 
+sabyasachi:x:1000:1000:Sabyasachi Paul,,,:/home/sabyasachi:/bin/bash 
+sssd:x:127:137:SSSD system user,,,:/var/lib/sss:/usr/sbin/nologin 
+
+This file has user account information. It is divided into 7 sections 
+In order, these fields are: 
+
+```
+- The username (root)
+- The user's password hash. In most cases the hash will not actually be given here and instead will be replaced with an `x`. This means that the hash can instead be found in `/etc/shadow`.
+- The user's UID (User ID) — as the root user, this is 0.
+- The user's GID (Group ID). For the root user this will also be 0.
+- A description of the account. This is simply "root" in the example, however, it can be left blank.
+- The user's home directory (/root)
+- The user's login shell (/bin/bash)
+
+e.g.: `user1`:`$1$123$LZ9RzzZZaryI4vY3ZLGhN0`:`0`:`0`:`iamroot`:`/root`:`/bin/bash`
+
+*If we can manually form our own entry (including a full password hash) and insert it into the passwd file then we can create a new user account. Interestingly, Linux doesn't check to confirm that the UID and GID of an account are unique — only that usernames are unique. In other words, we can create an account with our own unique username that has a UID and GID of 0, effectively giving our new account the same permissions as the root account!*