What is SUID and how to set SUID in Linux/Unix?

There are some other special permission apart from the normal file permissions read, write and execute which we set with chmod and chown commands. They are SUID, SGID, Sticky Bit, ACL’s, SUDO, SELinux for granular file/folder management by Linux administrator. Today we will see

1) What is SUID?
2) How to set SUID?
3) Where to use SUID?
What is SUID and how to set it in Linux?
SUID (Set owner User ID up on execution) is a special type of file permissions given to a file. Normally in Linux/Unix when a program runs, it inherits access permissions from the logged in user. SUID is defined as giving temporary permissions to a user to run a program/file with the permissions of the file owner rather that the user who runs it. In simple words users will get file owner’s permissions as well as owner UID and GID when executing a file/program/command.

The above sentence is a tricky one and should be explained in-depth with examples.
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