Things about git which I sometimes forget Recovering from a spaghetti branch Different ways of handling when you’ve branched from a branch, which later gets merged to a branch which you also want to merge to. rebase –onto You have created CURRENTBRANCH from OLDBRANCH which later got merged into NEWBRANCH. Now you want to clean up OLDBRANCH branch to reflect the real changes based on NEWBRANCH before a pull request. ...
Starting: mongo Connect to database show dbs use local See database tables show collections db.funnytable.find() Regex db.funnytable.find( $or: [ {'name': { $regex: req.params.username, $options: 'i' }}, {'username': { $regex: req.params.username, $options: 'i' }}, {'email': { $regex: req.params.username, $options: 'i' }} ])
Starting mysql # Same username, no password mysql -p # Password protected mysql -u user mysql -h hostname Create user CREATE USER me GRANT ALL PRIVILEGES ON database_name.* TO 'me'@'%'; ALTER USER 'me'@'%' IDENTIFIED BY 'newPass'; Connect to databaes SHOW DATABASES; SHOW DATABASES LIKE 'ok%'; USE mysql; See database tables SHOW TABLES; SHOW TABLES LIKE 'ok%'; SELECT * FROM important_stuffs; Extend tables ALTER TABLE important_stuffs ADD description VARCHAR(100); ALTER TABLE important_stuffs ADD description VARCHAR(100) AFTER severity; ALTER TABLE important_stuffs ADD description VARCHAR(100) FIRST; Delete from tables SELECT * FROM important_stuffs WHERE severity="low"; DELETE FROM important_stuffs WHERE severity="low"; Insert into tables INSERT INTO important_stuffs VALUES("Wow, so important", "high"); INSERT INTO important_stuffs SET description="Wow, so important", severity="high"; Show access rights SHOW GRANTS; Change all email addresses to my (when mailserver is activated) UPDATE users SET email= CONCAT('me+', id, '@iix.se'); General log show variables like 'general_log%'; SET GLOBAL general_log = 'ON'; SET GLOBAL general_log = 'OFF'; Run query without cache SELECT SQL_NO_CACHE * from users where name like 'Ol%'; Indexes SHOW INDEX FROM users; ALTER TABLE users ADD INDEX index_name(firstName); CREATE INDEX index_name ON users(firstName); ALTER TABLE users DROP INDEX users; DROP INDEX index_name ON users; Explain/describe EXPLAIN users; DESCRIBE users; DESC users; DESC SELECT * FROM users; Profiling SET SESSION profiling = 1; SHOW PROFILES; SHOW PROFILE FOR QUERY 3; SHOW STATUS LIKE 'Last_Query_Cost'; Collation show variables like "collation_database"; SELECT SCHEMA_NAME 'database', default_character_set_name 'charset', DEFAULT_COLLATION_NAME 'collation' FROM information_schema.SCHEMATA;
64 bits 32 bits 16 bits 8 bits rax eax ax al rbx ebx bx bl rcx ecx cx cl rdx edx dx dl rsi esi si sil rdi edi di dil rbp ebp bp bpl rsp esp sp spl r8 r8d r8w r8b r9 r9d r9w r9b r10 r10d r10w r10b r11 r11d r11w r11b r12 r12d r12w r12b r13 r13d r13w r13b r14 r14d r14w r14b r15 r15d r15w r15b Links 64-bit syscalls 32-bit syscalls
Links Full ncurses manual Apple Secure Coding C Gibberish (Decode C declarations) Some C #define tricks Cannot find stdio.h (or other headers) Install libc6-dev Case insensitive str(n)cpy #include <strings.h> int strcasecmp(const char *s1, const char *s2); int strncasecmp(const char *s1, const char *s2, size_t n); xmalloc void *xmalloc(size_t size) { void *ptr = malloc(size); if (ptr == NULL) { fprintf(stderr, "%s: Virtual memory exhausted\n", progname); abort(); } return ptr; } xrealloc void *xrealloc(void *ptr, size_t newsize) { ptr = realloc(ptr, newsize); if (ptr == NULL) { fprintf(stderr, "%s: Virtual memory exhausted\n", progname); abort(); } return ptr; } C Operator Precedence Operator - Description - Associativity () - Parentesis - Left-To-Right [] - Brackets . - Object member -> - Object member -- ++ - Postfix increment/decrement -- ++ - Prefix increment/decrement - Right-To-Left - + - Unary plus/minus ! ~ - Logic negation/complement (type) - Cast * - Dereference & - Address sizeof - Get typesize * / % - Multiply/Divide/Modulo - Left-To-Right + - - Addition/Subtraction << >> - Bitwise shift < <= - Relation less/less or equal > >= - Relation more/more or equal == != - Relation (not) equal & - Bitwise AND ^ - Bitwise XOR | - Bitwise OR && - Logical AND || - Logical OR ?: - Ternary - Right-To-Left = - Assignment += -= - Add/Sub assignment *= /= - Mult/Div assignment %= &= - Modulo / Bitwise AND assignment ^= |= - Bitwise (X)OR <<= >>= - BITWISE SHL / SHR ASSIGNMENT