origin SchemaSQLHas to define schema before using it. Primary Key Relation Index Trigger Store Procedure Constrain This makes the SQL very stable but not easy to change. Whenever you change, you nee

1cut OPTION... [FILE]... 123456$ cat state.txtAndhra PradeshArunachal PradeshAssamBiharChhattisgarh -bextract single character one character123456$ cut -b 1,2,3 state.txtAndAruAssBihChh consecutiv

Inner JoinNatural JoinAutomatically join tables by their column name. 123select *from registration natural join course Normal Joinmanually specify the column name to join 1234select *from registrati

CloneUse load balance to distribute user request. Every server contains exactly the same codebase and does not store any user-related data, like sessions or profile pictures, on local disc or memory.

12sort [_OPTION_]... [_FILE_]... sort [_OPTION_]... _--files0-from=F_ parameter option description -k sort by particular column -b Ignores leading blanks. -d Considers only blanks and alpha

1tr [OPTION] SET1 [SET2] replace1cat content | tr “[:lower:]” “[:upper:]” -ccomplements the set of characters in string.i.e., operations apply to characters not in the given set 1echo "my ID

Subset without duplication12345678910111213141516// https://leetcode.com/problems/subsets/public List<List<Integer>> subsets(int[] nums) { List<List<Integer>> list = ne

nexus staging pluginnexus-staging-maven-plugin is a plugin just for nexus related repositories.In order to release into maven central repository, you need to pass all checks that acquired by central r

很多人都说高中是他们记忆最深刻的时光，因为在一个高压的状态下，一群人努力奋斗，而目标又是如此明确；也有说大学是他们最怀念的岁月，因为青春可以随意的挥霍，从高压状态下解放出来，不少人选择做一些疯狂的事情，那些疯狂的记忆让他们非常留恋。 是让我记忆最深刻，感觉最开心，有时候又最心酸的时光，是属于13岁到15岁的初中时代。 在那个十分懵懂的岁月里，被迫从一个完全不懂为什么要这样那样做的人，变为一个必须要

Create12gpg --gen-keygpg --full-generate-key Delete12gpg --delete-keys $UIDgpg --delete-secret-keys $UID List key12gpg --list-key #list public keygpg --list-secret-keys #list private key Encrypt12g