apktool

apktool d <APK_FILE>

proxy

# /etc/apt/apt.conf
Acquire::http::Proxy "http://10.90.50.122:8889";

print nth to last

Using awk to print all columns from the nth to the last

# Print all but the first column
awk '{$1=""; print substr($0,2)}' somefile
# Print all but the fisrt two columns
awk '{$1=$2=""; print substr($0,3)}' somefile

delimiter

SO: awk delimiter

awk -F'[, ]' '{print $1 " " $2}'

sum column

awk '{sum+=$1} END {print sum}'

args length

$# # not include command
$ miao.sh wang # $# is 1

args range

same to array

${@:3:2} # from position 3, length 2
${@:3} # from position 3, to last

cd last dir

参考bash手册关于cd的说明

# 等价于cd $OLDPATH
cd -

commentable string concat

CMD=(
    "args"
    "${OTHER_ARGS[@]}"
)
eval "${CMD[@]}" # "${CMD[*]}"

conditional constructs

gnu bash manual 3.2.5.2

if test-commands; then
  consequent-commands;
[elif more-test-commands; then
  more-consequents;]
[else alternate-consequents;]
fi

• if its return 0,
  • consequent-commands are executed

exit on fail

set -o errexit

func src file

SO: find definition of bash func

shopt -s extdebug
declare -F <func>
shopt -u extdebug

here document

COMMAND <<InputComesFromHERE
# ...
InputComesFromHERE

parallel execution

SE: bash parellel exec

N=4
for i in {a..z}; do
  (
    # do your stuff here
  ) &
  if [[ $(jobs -r -p | wc -l) -ge $N ]]; then
    wait -n
  fi
done
wait
echo all done

print command

# see `help set`
set -x # turn on
set +x # turn off

read file lines

while read line
do
    echo "$line"
done < file

test a var is num

How do I test if a variable is a number in Bash?

re='^[0-9]+$'
if [[ $yournumber =~ $re ]]
then
   echo "is a num!"
fi

trace

set -o xtrace

i386

echo ':i386:M::\x7fELF\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02\x00\x03:\xff\xff\xff\xff\xff\xfe\xfe\xff\xff\xff\xff\xff\xff\xff\xff\xff\xfa\xff\xff:/usr/local/bin/qemu-i386:' >/proc/sys/fs/binfmt_misc/register

qemu

sudo ./scripts/qemu-binfmt-conf.sh  --qemu-path /usr/local/bin/qemu-x86_64 --systemd x86_64

x64

echo ':x64:M::\x7fELF\x02\x01\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02\x00\x3e\x00:\xff\xff\xff\xff\xff\xfe\xfe\x00\xff\xff\xff\xff\xff\xff\xff\xff\xfe\xff\xff\xff:/usr/local/bin/qemu-x86_64:' >/proc/sys/fs/binfmt_misc/register

NOTED

cmake use CMakeCache.txt

If meet unexpected behavior,

clean all cmake generated files

compile_command.json

-DCMAKE_EXPORT_COMPILE_COMMANDS=1

log

• CMakeFiles/CMakeError.log
• CMakeFiles/CMakeOutput.log

build show stdout

SO

--progress=plain

ls containers

docker ps -as

ls imgs

docker images -a

prune

docker system prune

rm all-containers

docker ps -aq | xargs docker rm

rm all-imgs

docker images -aq | xargs docker rmi

rm container

docker rm <containers>

rm img

docker rmi <images>

rm untagged-img

podman images | grep "^<none>" | awk '{print $3}' | xargs podman rmi

stop containers

docker stop <containers>

build

podman build --network=host -t <tag>

image mount

podman unshare
podman image mount <image>

run

podman run --rm --network=host -it <image>

debugger

SO: gdb in docker

--cap-add=SYS_PTRACE

extract bytes from file

https://stackoverflow.com/questions/1423346

Noted: dd only take decimal number, 0x prefix does not work.

dd skip=<start> count=<size> if=<input> of=<output> bs=1

dd

dd if=<INPUT/PATH> of=/dev/<OUTPUT> status=progress

disk usage

df -h

file folder-size

du -sBM * | sort -n

查看meta info，例如pdf，详细见man

exiftool -Title=<title> <file>
exiftool -Author=<author> <file>

example

http://www.figlet.org/examples.html

fonts

/share/figlet/*.flf

list

SE: get name of font

SO: get name of fonf

fc-list
fc-scan

google-fonts

repo: GH: google/fonts/ofl/

search: fonts.google.com

grub

SE: customize GRUB font size

sudo grub-mkfont -s 36 -o /boot/grub/fonts/DejaVuSansMono.pf2 /usr/share/fonts/truetype/dejavu/DejaVuSansMono.ttf
fc-list
vim /boot/grub/grub.cfg

tty

SE: otf to psf

reddit: ttf to psf

dpi cal

otf2bdf -r 242 -p 36 /usr/share/fonts/truetype/dejavu/DejaVuSansMono.ttf -o ~/Desktop/DejaVuSansMono.bdf

increase disk

Increase qcow2 2GB

qemu-img resize <.qcow2> +2G

Inside FreeBSD

camcontrol reporbe ada0
# find out index
gpart show
gpart resize -i <index> ada0
growfs /

linuxulator

FreeBSD: Linux Bin Compat

# edit /etc/rc.conf
linux_enable="YES"

service linux start

default -march

gcc -Q --help=target

inline asm

No clobber, may segment fault! Just an example.

#include <stdio.h>
int a = 10;
int b = 20;
int result;
int main(void)
{
   asm( "mov a, %eax\n\t"
        "mov b, %ebx\n\t"
        "add %ebx, %eax\n\t"
        "mov %eax, result");
   printf("the result is %d\n", result);
   return 0;
}

extended inline asm

#include <stdio.h>
int a = 10;
int b = 20;
int result;
int main(void)
{
   asm( "mov a, %%eax\n\t"
        "mov b, %%ebx\n\t"
        "add %%ebx, %%eax\n\t"
        "mov %%eax, result"
        : /* no outputs*/
        : /* no inputs */
        : "eax", "ebx");
   printf("the result is %d\n", result);
   return 0;
}

predefined macros

2012.SO: preprocessor defined macros

gcc -dM -E - < /dev/null
touch bla.c && gcc -dM -E bla.c

text segment addr

SO

gcc -static -Wl,-Ttext=0x1000 <Args>

frame

bt
frame <bt num>
info frame <bt num>
info locals

terminology

Simulation Mode

• Full System (FS)
• Syscall Emulation (SE)

cache

• mshr: Miss Status Handle Register
• tgt: ?[TODO]

generate hh from py

# generate header from MyMemObject.py
scons build/ARM/params/MyMemObject.hh

generate doxygen

output: src/doxygen/html

cd src
doxygen

SE (syscall emu)

gem5.opt configs/example/se.py --cmd <CMD>

create Repos/*

# can use git update then
git clone --mirror <URL>

convert bare to mirror

SO

git config remote.origin.fetch "+refs/*:refs/*" 
git config remote.origin.mirror true

remote branches

列举remote的分支

# 无需联网
git branch -r [-l <patthern>]
# 需要联网
git remote show <remote>
git ls-remote <remote>

查找删除某行的commit

SO: find removed line

# 面对merge节点似乎有问题
git log -c -S'<string>' <file>
git log -c -G'<regex>' <file>
# 然后搜索
/<string>

clone server-Codes

git clone git://10.90.50.99/<REPO>

clone specific-tag

git clone -b <tag> --depth=1 <repo>

list remote-tags

git ls-remote --tags <repo>

rebase interactive

# root commit
git rebase -i --root
# non-root commit
git rebase -i <commits>

server Codes

git daemon --base-path=/home/xieby1/Codes/ --export-all

create uncommit patch

create uncommit patch

git diff > <xxx.patch>

visualization

SO: git visualization

# simplified
git log --all --decorate --oneline --graph --simplify-by-decoration
# full
git log --all --decorate --oneline --graph

only filename

Scanning each input file stops upon first match.

Therefore, it is fast!

grep -l

register

sudo docker exec headscale headscale -n <NETWORK> nodes register --key <KEY>

reset login server

tailscale up --force-reauth --reset

rm node

sudo docker exec -it headscale headscale nodes del -i <ID>

exec cmd

sudo docker exec headscale headscale --help

client register

sudo tailscale --socket <PATH> up --login-server <URL>[:PORT]

detail

fold/collapse/expand

<details>
  <summary>Details</summary>
  miao
</details>

span color

<span style="background: red; color: white; font-weight: bold;">

time stamp

<div style="text-align:right; font-size:3em;">2022.04.12</div>

get dimension/size

identify <image>

extract pdf

Poppler/Cairo import (Huge size)
<Ctrl><Shift>G # ungroup
! # invert selection
<Ctrl><Shift>R # resize canvas
Extensions->Text->Replace Font

edit/view mode

ctrl+shift+m

MIT

• 随意使用
• 保留该MIT许可
• 作者不负责

编译

make defconfig && make

版本号

include/config/kernel.release
make menuconfig: General setup -> Local version

安装

make INSTALL_PATH=<path> install
make INSTALL_MOD_PATH=<path> modules_install

生成源码跳转文件

# 需要先编译
./scripts/clang-tools/gen_compile_commands.py
make ARCH=x86 COMPILED_SOURCE=1 cscope

内部结构

符号表WP: System.map

由nm生成，符号类型见man nm

• 内核暴露的符号/proc/kallsyms
• 或是由源码生成System.map

系统调用表sys_call_table

内核信息重定向

ref: dmesg output to tty

x86上不可靠：输出不全，几次就关闭了

tty # `who am i` may not output
cat /proc/kmsg > <stdio dev file>

mod

show info about a mod

modinfo <mod>

generate ll

clang -S -emit-llvm <file.c> -o <file.ll>

generate bc

clang -c -emit-llvm <file.c> -o <file.bc>

run ir

lli <file.ll/bc>

terminology

# a rule
target … : prerequisites …
    recipe
    …

all executables

EXECUTABLES=$(patsubst %.cpp, %, $(wildcard *.cpp))
all: ${EXECUTABLES}

clean executables

SO: How do I execute each command in a list?

define \n


endef
$(foreach x,${EXECUTABLES},rm ${x}${\n})

func wildcard

$(wildcard pictures/*.drawio)

grouped targets

make manual: multiple targets

foo bar biz &: baz boz
        echo $^ > foo
        echo $^ > bar
        echo $^ > biz

hash dep

GH: hashdeps

include hashdeps.mk
combined.txt: $(call hash_deps,a.txt b.txt)
    echo "Concatenating files"
    cat $(call unhash_deps,$^) > $@

implicit rule

%:%.c
    $(CC) $< -o $@

grouped target

make manual

foo bar biz &: baz boz
        echo $^ > foo
        echo $^ > bar
        echo $^ > biz

prerequisite

$< # first
$^ # all
$(word 2,$^) # second

target依赖树

SO: makefile dependency tree

make -nd <target> | make2graph
# makefile2graph <target>

列出所有targets

remake --targets

proxy

https://maven.apache.org/guides/mini/guide-proxies.html

<settings>
  <proxies>
   <proxy>
      <id>example-proxy</id>
      <active>true</active>
      <protocol>http</protocol>
      <host>proxy.example.com</host>
      <port>8080</port>
      <username>proxyuser</username>
      <password>somepassword</password>
      <nonProxyHosts>www.google.com|*.example.com</nonProxyHosts>
    </proxy>
  </proxies>
</settings>

build

同名md和html html优先

dns resolve

host <domain name>

scan local

nmap 192.168.1.0/24

connect hidden wifi

wpa_cli connection to hidden ssid

> add_network x
> set_network x ssid "hidden_ssid"
> set_network x psk "secret"
// ALLOW CONNECT TO HIDDEN SSID
> set_network x scan_ssid 1
> enable_network x
> save_config
> select_network x

raspberrypi ubuntu netplan

# /etc/netplan/50-cloud-init.yaml
network:
  version: 2
  wifis:
    renderer: networkd
    wlan0:
      access-points:
        <name>:
          password: <...>
          hidden: true
      dhcp4: true
      optional: true

tesseract

# 列支持的语言
tesseract --list-langs

ocrmypdf

详细见ocrmypdf.md

ocr会将原pdf栅格化，

所以需要分离文本和图片

# 去除文本
gs -o notext.pdf -dFILTERTEXT \
-sDEVICE=pdfwrite <input.pdf>
# 运行ocr
ocrmypdf --force-ocr --output-type pdf \
-l $lang notext.pdf ocr.pdf
# 去除图片仅保留文本
gs -o textonly.pdf -dFILTERIMAGE \
-dFILTERVECTOR -sDEVICE=pdfwrite ocr.pdf
# 叠加文本
qpdf notext.pdf --overlay \
textonly.pdf -- <output.pdf>

可用代码高亮

pandoc: syntax highlighting

pandoc --list-highlight-languages

打印默认模板

pandoc -D <FORMAT>

print default styles

--print-default-data-file=templates/styles.html

home (tilde)

write ‘~’ to file home

parallel --tag ssh {1} ls {2}/Codes ::: myloongson55 myloongson56 myloongson57 myloongson58 :::: ./home

parallel --tag ssh {1} ls \\~/Codes ::: myloongson55 myloongson56 myloongson57 myloongson58

man/doc

perldoc perlrun

sed like rexeg lookbehind

sed lookbehind

perl -pe 's/(?<=foo)bar/test/g' file.txt

jpgs2pdf

convert input1.jpg input2.jpg input3.jpg output.pdf

resize

convert input.xxx -resize 100x200\! output.xxx

apk

apk info -L <pkg>

deb

dpkg-deb -c <package_name.deb>

installed

dpkg-query -L <package_name>

not installed

apt-file list <package_name>

host net

10.0.2.2

smb

mount -t cifs -o user=miao%miao //10.0.2.4/qemu Host/

system file disk

[qemu-sys] -m 16 -nographic -fda [file]

tcg/

• tcg.c, tcg-op.c: generate tcg
• /: tcg =>
• tci.c: tcg => interpreting
• README: tcg syntax intro

quickemu

quickemu --display none --vm ~/Img/ubuntu-22.10.conf
# cat ~/Img/ubuntu-22.10/ubuntu-22.10.ports
ssh quickemu

OSX-KVM

./OpenCore-Boot.sh

utm

ssh forward by useing emulated vlan

align

SO: center child divs inside parent div

:::{style="display:inline-block; text-align:left;"}
things here are all

left aligned

!
:::

chalkboard

del: clear current
backspace: clear all
c: note canva
b: chalkboard
d: download drawings
x: previous color
y: next color
right click: eraser

fragments fade

revealjs fragments

fragments highlight

fragments others

fragments order

<p class="fragment" data-fragment-index="3">Appears last</p>
<p class="fragment" data-fragment-index="1">Appears first</p>
<p class="fragment" data-fragment-index="2">Appears second</p>

print pdf

Append ?print-pdf to URL.

toc style

<style>nav {...}<style>

TODO: yaml_metadata_block

add

sudo route add -net 172.17.103.0 \
gw 10.90.50.254 \
netmask 255.255.255.0 \
metric 1000 \
dev enp9s0

del

sudo route del -net 172.17.103.0 \
gw 10.90.50.254
netmask 255.255.255.0 \
dev enp9s0

installed targets

rustup show

交叉编译

rustc --print target-list
rustup target add <TARGET>
cargo build --target=<TARGET> --release

clean

scons -c

otg mouse/keyboard

GH: barrier: Please make an Android client

# In this mode, adb (USB debugging) is not necessary
scrcpy --window-width 100 --window-height 100 --otg -s DEVICEID

overview

• detailed document
  • gnu sed manual
• brief synopsis
  • man sed

terminology

[addr]X[options]
[addr]{X1[options]; X2[options]; ...}

regex

POSIX.2 BREs

• gnu sed manual
• wikibooks: POSIX BREs

recursive all files

SO

• -print0

  results separated by null char

find . -type f -print0 | \
xargs -0 sed -i 's/.../.../g'

if match

if match return 1

else return 0

sed '/<pattern>/Q 1'

new line

SO: How replace a newline

sed -z 's/\nwang\nmiao\n//g'

refer to match

sed 's/\(.*\)miao/\1wang/g'

all

// command line:
//   dot -Tsvg -O sixu.dot


digraph {
// attributes
/// graph
rankdir=BT;
/// subgraph
newrank=true;
style=filled;
//// color name: https://graphviz.org/doc/info/colors.html
color=whitesmoke;
/// node
node[
shape=box,
style="filled, solid",
color=black,
fillcolor=white,
];
/// edge
edge[
minlen=1,
//weight=1,
// If false, the edge is not used in ranking the nodes.
//constraint=true,
];



}

today

"22Apr12+" -> "22Apr12-" -> "22Apr12+";
subgraph cluster_22Apr12
{
x22Apr12_
}
{rank=same;
"22Apr12-";
x22Apr12_
}
{rank=same;
"22Apr12+";
}

bind address

ssh -L 8890:example.org:8889 -N -T username@remote_host

nixos x forward

ssh -Y

create swapfile

sudo fallocate -l 4G /swapfile
# optional
sudo chmod 600 /swapfile
sudo mkswap /swapfile
sudo swapon /swapfile

After/Before说明

man systemd.unit

man pages

• systemd
• systemd.unit
• systemd.syntax
• systemd.service

user目录

man systemd.unit

~/.config/systemd/

service状态

systemctl --user status <service>
journalctl --user -u <service>

service output

# sys
journalctl -f -u <service>
# user
journalctl --user -f -u <service>

列举unit类

# 例如列出list
systemctl list-units --type target

auto login

ubuntu auto login

#Create the directory:
sudo mkdir /etc/systemd/system/getty@tty1.service.d
#Create file:
sudo vim /etc/systemd/system/getty@tty1.service.d/autologin.conf
#Insert:
[Service]
ExecStart=
ExecStart=-/sbin/agetty --autologin YOURUSERNAMEHERE --noclear %I 38400 linux

auto swapon

[Unit]
Description=Swapon

[Install]
WantedBy=default.target multi-user.target

[Service]
ExecStart=swapon /swapfile

create directory

# NOTED: no ./ before dir !!!
tar czf bin.tar.gz <dir>

auto start tmux

[[ $TERM != "screen" ]] && exec tmux

terminology

man tmux: Description

• session
  • window
    • pane = pseudo terminal (pty)

Any number of tmux instances can

cnnect to the same session.

split

<C-b> " // vertical
<C-b> % // horizontal

regedit

• Regedit
• Useful Registry Keys
• wine regedit /?

wslcompact

https://github.com/okibcn/wslcompact

shrink vdisk

wsl --shutdown
diskpart
select vdisk \
file="C:\Users\<User>\AppData\Local\ \
Packages\CanonicalGroupLimited.UbuntuonWindows... \
\LocalState\ext4.vhdx"
compact vdisk

restart server

Alt-F2
r

Xephyr

Xephyr :2 -resizeable  -dpi 48 -host-cursor

DISPLAY=:2 <command>

multiple DPI

Mixed DPI

SE: cursor flicker

xrandr --output DP-1 --scale-from 2880x1800
# Stop flicker
xrandr --output eDP-1 --scale 0.9999x0.9999

x0vncserver

x0vncserver -password <PSWD> -securitytypes=none -geometry 800x600+0+480 -FrameRate 10

xdg-mime

xdg-mime query filetype <file>
xdg-mime query default <type>

add

yarn global add node_module

bin

yarn global bin

alacritty search

C-S-f
Enter
S-Enter

ccls

.ccls file

clang
-I<PATH>
-D<VAR>

crypt

perl -e "print crypt('wjxby','xb');"

combine pdf

pdftk <file1.pdf …> cat output <output.pdf>

dgen-sdl

dgen <path>

flame graph

https://github.com/brendangregg/FlameGraph

sudo perf record -g <cmd>
sudo perf script > out.perf
stackcollapse-perf.pl out.perf > out.folded
flamegraph.pl out.folded > out.svg

gnome autostart

gnome autostart programs

mov desktop file to

~/.config/autostart/

gnome desktop spec

https://developer-old.gnome.org/desktop-entry-spec/

gnome dock new window

TODO: dash-to-dock? or original dock?

ctrl+super+<num>

open desktop file

gtk-launch <xxx.desktop>

gprof

# compile
gcc ... -gp
# run <file>
# show
gprof <file>

kitty ssh

SO: tmux kitty

kitty +kitten ssh myserver

second-level servers

kitty +kitten ssh -J jump_server destination_server

pkg-config

# 获取package的名字
pkg-config --list-all | grep <xxx>
# 获取c编译、链接参数
pkg-config --cflags --libs <pkg>

pdftohtml

pdftotext -noframes -i -q -p -c <pdf>

pdftotext

pdftotext -q <pdf>

进程树

ps -jHg <pid> # 进程子树
pstree -psal <pid> # 完整树

new user

adduser xieby1
usermod -aG sudo xieby1

drawio no snapping

SE: no arrows snapping

hold ctrl + shift

iconv

# 文本编码转换
iconv -f gb18030 -t utf-8 <output>

pipe clipboard

 | xclip -selection clipboard

shebang with arguments

SE: Multiple arguments in shebang

#!/usr/bin/env -S cmd arg1 arg2 ...

sort first column

sort -s -n -k 1,1

calibrate touchscreen

SO: Calibrate one touch one not

xinput --map-to-output $(xinput list --id-only "WingCoolTouch WingCoolTouch") DP-1

clang-format config

clang-format -style=llvm -dump-config > .clang-format

clang-format on/off

// clang-format off
...
// clang-format on

debug script

import pdb
pdb.set_trace()

object attr

dir()
vars()

pyright ignore

ignore one line

<code needed to be ignored> # type: ignore

pyright local conf

https://microsoft.github.io/pyright/#/configuration

# pyrightconfig.json
{
  reportGeneralTypeIssues = false,
}

requirement syntax

requirements.txt

• Requirement Specifiers
  • PEP 508

E.g.

requests [security] >= 2.8.1, == 2.8.* ; python_version < "2.7"

pdf

chinese support compromise

use rsvg-convert to convert

rcParams

default matplotlibrc file

svg

svg able to copy, support chinese

plt.rcParams["svg.fonttype"] = "none"

list all

:buffers " or
:ls " or
:files

delete

:bdelete

open/edit

" tab key works
:buffer <name>

debug log

SO: runtime log

vim -V9myVim.log

Explore (netrw)

; open current file's dir
:E[xplore]

Explore crash (netrw)

rm ~/.local/share/nvim/.netrwhist

Increase column

c-v ; select block
g c-a

insert stdout

; insert below
:r!<cmd>
; insert above
:-r!<cmd>
; insert top
:0r!<cmd>

lower/upper case

In select mode

u ; lower case
U ; upper case

netrw new file

# in netrw mode
%

fold

" set
zf{motion} " :h motion.txt
" toggle
za
" range
:{range}fo[ld]

highlight current line

:set cursorline

list syntaxs

ls <$VIMRUNTIME>/syntax/

markdown toc

:GenTocGFM

mapped keys

SO

":n/v/imap
:map
:h inex

popup window

🐁 <leader>[

runtime folder

:echo $VIMRUNTIME

split调整

c-w _ ; max height
1c-w _ ;min height
c-w = ;same height
:on ; close others
c-w o ;same above

filetype syntax bindings

<$VIMRUNTIME>/filetype.vim

scrollbind

:set scrollbind
:set noscrollbind

set filetype (nvim)

it can control syntax and coc

set filetype=python

set syntax

:set syntax=

syntax

; set
:set syntax=html
; get
:set syntax

status line

set laststatus=2

jumplist

:ju " 列出jumplist
<C-o> " 退
<C-i> " 进

cscope

; cs querytype
🐁 <C-\>[sgdcteFia]

重新加载

:!cscope -R
:cs reset

mark

<leader>m " 标记/取消标记
{N}<leader>m " 给第N组添加标记词
{N}<leader>n " 取消第N组的标记
<leader>M " 显示标记颜色和标记词
🐁 <leader><F3> " 取消所有标记

ale-fix

ale支持的fix位于

autoload/ale/fix/registry.vim

所有fixer的调用脚本位于

autoload/ale/fixers/

wrap line

; 🐁toggle
<F9>

terminal mode

:h :terminal

# exit temrinal mode
<C-\><C-N>
# enter temrinal mode
i

diffthis

diff两个竖分buffers

; 分别在两个buffer里
:difft[his]
; 关闭，分别
:diffoff

gitgutter-diff

let g:gitgutter_diff_base = ''
:GitGutterDiffOrig

diff obtain/put

" obtain
do
" put
dp

blame [# fugitive]

和git相同的略。fugitive的特性：

:Git blame " blame整个文件
:Gedit " 跳转光标下到对应的object（某个版本的某个文件）

historic file [# fugitive]

Gedit <refname>
enter " opon
o " horizon open
O " new tab open
<num>gt " switch tag

显示commit信息 [git-messenger]

<leader>gm " 在popup窗口显示commit信息

AnsiEsc

:AnsiEsc

config-local

~/.local/share/nvim/config-local

:ConfigSource
:ConfigEdit
:ConfigTrust
:ConfigIgnore

git-wip

trigger every time :w,

or trigger manually

:call GitWipSave()

lightspeed.nvim

s ; forward
S ; backward

tree-sitter update

GH Issue: query.lua query: error at position #759

:TSUpdate

tree-sitter reinstall

:TSUninstall all
; exit vim
home-manager switch
vim
:TSUpdate

coc disable

:CocDisable
:CocEnable

coc disable diagnostic

:e reload file is neccessary

:let b:coc_diagnostic_disable=1
:e

by column

:h /\%c

\%23c   Matches in a specific column.
\%<23c  Matches before a specific column.
\%>23c  Matches after a specific column.
\%.c    Matches at the cursor column.
\%<.c   Matches before the cursor column.
\%>.c   Matches after the cursor column.

check

# list all DIR/FILE
zellij setup --check

paths

<nix channel url>/store-path.xz

e.g. https://mirror.tuna.tsinghua.edu.cn/nix-channels/nixos-21.11/store-paths.xz

query

refers to Discourse: Is it possible to query the binary cache?

nix path-info \
--store https://cache.nixos.org/ \
-f '<nixpkgs>' \
--argstr system x86_64-linux \
<pkgs-name>

import/export

# import may need sudo
nix-store --import/--export

copy

How to use a local directory as a nix binary cache?

nix copy --no-check-sigs \
--to <output/path> </nixstore/path>
nix-env -i <output/path>

verify

nix-store --verify [--check-contents] [--repair]

get closure paths

nix-store -qR

copy closure

sudo nix-copy-closure --from <user@ssh> <path>

force update

nix-channel --option tarball-ttl 0 --update [<channel>]

manual

man nix.conf

show

nix show-config

nixos

/etc/nixosconfiguration.nix

{
  nixpkgs.config = {
    allowUnfree = true;
  };
}

nix user

~/.config/nixpkgs/config.nix

{
  allowUnfree = true;
}

proxy

Nix manual: Proxy Environment Variables

/etc/systemd/system/nix-daemon.service.d/override.conf

setup

nix-shell
. $stdenv/setup

nix-build

nix-build -K <drv>

nix-build

nix-build '<nixpkgs>' -A xxx

find referrers

nix-store --query --referrers <nix-path>

find references

nix-store --query --references <nix-path>

eval

nix eval --expr "<EXPR>"

.desktop

~/.nix-profile/share/applications

sysconfig

GH: sysconfig

sysconfig = (import <nixpkgs/nixos> {}).config;

sys garbage

sudo nix-collect-garbage -d

usr garbage

nix-collect-garbage -d

nix-build garbage

ls -l /nix/var/nix/gcroots/auto

direnv garbage

ls -l /nix/var/nix/gcroots/per-user/<user>

build pkg

nix-build '<nixpkgs>' -A <pkg>

cheatsheet

NixOS Wiki Cheatsheet

disable gcc hardening in shell

SE: Disabling the security hardening options for a nix-shell environment

export NIX_HARDENING_ENABLE=""

nix direnv

echo "use nix" >> .envrc
direnv allow

gnome extension

pkgs/desktops/gnome/extensions/extensions.json

prefetch url

nix-prefetch-url

prefetch github

nix-prefetch-url --unpack \
https://github.com/<owner>/
<repo>/archive/<rev>.tar.gz

prefetch sha256

GH

nix-prefetch-url --unpack

sha256

nix-hash --type sha256 \
--flat --base32 <file>

size

# man nix3-path-info
# closure-size
nix path-info -Sh <path>

show drv

nix show-derivation <.drv>

repl

pkgs = import <nixpkgs> {}

old generations

Nix Wiki: Storage Opt

sudo nix-env -p /nix/var/nix/profiles/system --list-generations
sudo nix-collect-garbage -d
# User Generations (Home-Manager)
nix-collect-garbage -d

path

Nix Pills: search Paths

nix-instantiate --eval -E "<path>"

version

nix-version --hash

nix-on-droid sshd

sshd-start

home-manager option

home-manager option <OPTION>

nixos-option

​bash nixos-option <OPTION>

types

possible dependency types and examples

examples

possible dependency types and examples

TODO: simplify

• g++ links against the host platform’s glibc C library, which is a “host→ ” dependency with a triple of (bar, bar, ). Since it is a library, not a compiler, it has no “target”.

• Since g++ is written in C, the gcc compiler used to compile it is a “build→ host” dependency of g++ with a triple of (foo, foo, bar). This compiler runs on the build platform and emits code for the host platform.

• gcc links against the build platform’s glibc C library, which is a “build→ ” dependency with a triple of (foo, foo, ). Since it is a library, not a compiler, it has no “target”.

• This gcc is itself compiled by an earlier copy of gcc. This earlier copy of gcc is a “build→ build” dependency of g++ with a triple of (foo, foo, foo). This “early gcc” runs on the build platform and emits code for the build platform.

• g++ is bundled with libgcc, which includes a collection of target-machine routines for exception handling and software floating point emulation. libgcc would be a “target→ ” dependency with triple (foo, baz, ), because it consists of machine code which gets linked against the output of the compiler that we are building. It is a library, not a compiler, so it has no target of its own.

• libgcc is written in C and compiled with gcc. The gcc that compiles it will be a “build→ target” dependency with triple (foo, foo, baz). It gets compiled and run at g++-build-time (on platform foo), but must emit code for the baz-platform.

• g++ allows inline assembler code, so it depends on access to a copy of the gas assembler. This would be a “host→ target” dependency with triple (foo, bar, baz).

• g++ (and gcc) include a library libgccjit.so, which wrap the compiler in a library to create a just-in-time compiler. In nixpkgs, this library is in the libgccjit package; if C++ required that programs have access to a JIT, g++ would need to add a “target→ target” dependency for libgccjit with triple (foo, baz, baz). This would ensure that the compiler ships with a copy of libgccjit which both executes on and generates code for the baz-platform.

• If g++ itself linked against libgccjit.so (for example, to allow compile-time-evaluated C++ expressions), then the libgccjit package used to provide this functionality would be a “host→ host” dependency of g++: it is code which runs on the host and emits code for execution on the host.

propagation

dependency propagation

fetch

pkgs/build-support/fetch.*/

mkDerivation

nix manual: advanced-attrs

pkgs/stdenv/generic/make-derivation.nix

.override

• override {…}
  • override arguments
• overrideAttrs (old: {…})
  • override attrs before mkDerivation

indented string

''
  # escape ${
  ''${bash_var}
  # escape ''
  '''
''

Nix manual: values

<path>, like <nixpkgs>, is path

listed in env NIX_PATH

args

SO: import module with

# foobar.nix
{lib, withFoo ? "bar", ...}:
{# ...}

# configuration.nix
args@{ ... }:
{imports = [(
  import ./foobar.nix (args // { withFoo = "baz"; })
)];}

list build-generations

sudo nix-env -p /nix/var/nix/profiles/system --list-generations

build env

nix-shell '<nixpkgs>' -A <pkg>

direnv

use nix <path>

direnv fhs

if [[ -z "$IN_NIX_SHELL" ]]; then
  use nix <path>
fi

patchShebangs

patchShebangs <path>

non-interp shebang

Inspired by cursed.nix

My tests show, as long as there are arguments in nix-shell, the interp mode of nix-shell is not triggered!

Therefore, I change -v to --keep miao

Why it works?

#!/usr/bin/env -S nix-shell --keep miao

bundle

# nix built-in
nix bundle
# github 465 start
nix-bundle

dependency

# all dependencies
nix-store --query --requisites </nix/store/path>
## or
nix-store --query -R </nix/store/path>
# nested tree
nix-store --query --tree </nix/store/path>
# only immediate dependencies
nix-store --query --references </nix/store/path>

nix-tree

nix-tree </nix/store/path>

not in nixpkgs

nix-shell -E "with import <nixpkgs> {}; callPackage ./default.nix {}"

priority

lib.lowPrio <pkg>

search file

nix-locate 'bin/hello'

python

pkgs/top-level/python-packages.nix
pkgs/development/python-modules/
pkgs/development/interpreters/python/mk-python-derivation.nix

python3 gi

pyobject3

tex live

pkgs/tools/typesetting/tex/texlive/pkgs.nix

static

SO: How to produce static executable on NixOS?

pkgs.glibc.static
pkgs.zlib.static

help

:?

open editor

:e <expr>

home-manager

refers to nix repl home.nix config

hm = import <home-manager/modules> { configuration = ~/.config/nixpkgs/home.nix; pkgs = import <nixpkgs> {}; }

musl libc

Support -static

nix-shell -p pkgsCross.musl64.stdenv.cc
x86_64-unknown-linux-musl-gcc -static hello.c

static compile

Nix currently use musl-gcc

nix-shell -p pkgsStatic.stdenv.cc
x86_64-unknown-linux-musl-gcc -static hello.c

aarch64 cross

nix-shell -p pkgsCross.aarch64-multiplatform.stdenv.cc
aarch64-unknown-linux-gnu-gcc

cond code

2021.armv8.pdf: C1.2.4: Table C1-1

cond flags

2021.armv8.pdf: B1.2.2 2021.armv8.pdf: C5.2.9

// gdb: p cpsr # Current Program Status Register
// 6     333222       | N: Negative
// 3 ... 210987 ... 0 | Z: Zero
//  RES0  NZCV  RES0  | C: Carry (unsigned)
//                    | V: Overflow (signed)
//
mrs x1, NZCV // get NZCV
msr NZCV, x1 // set NZCV

page size (Manual)

2021.armv8.pdf:

• D5.2.7:
  • granule & block size
• D5.5.6
  • The Contiguous bit

page size (Linux)

arch/arm64/mm/hugetlbpage.c

ldst align

2021.armv8.pdf

B2.5.2

• Load or Store of Single or Multiple regs
• Load/Store-Exclusive and Atomic insts
• Non-atomic Load-Acquire/Store-Release insts

Exception levels

refs

📑 Arm Architecture Reference Manual Armv8

addr

• normal: [x1]
• offset: [x1, #12]
• pre-index: [x1, #12]! // x1+=12, addr=x1
• post-index: [x1], #12 // addr=x1, x1+=12

no cmov?

2014: SO: arm no conditinal execution

ptr auth

• 2017: LWN
• § Pointer authentication in AArch64 state

arm linux only use bottom 40 bits of a pointer

pointer[63:40] = PAC(pointer[39:40], key, modifier)
AUT(pointer[63:40], pointer[39:40], key, modifier)

five separate keys:

• two for executable (instruction) pointers
• two for data pointers
• one generic pointers

ldtr, sttr

SO: Load/Store unprivileged

ldnp, stnp

ARMv8

Non-temporal load and store pair

Hint mem system no cache, typically in streaming data.

ldaxr, stxr

DynamoRIO: Exclusive Monitor

E.g. an atomic subtract

1f404:   ldaxr   w1, [x0]
1f408:   sub     w2, w1, #0x1
1f40c:   stxr    w3, w2, [x0]
1f410:   cbnz    w3, 1f404

cannot be nested,

as each hardware thread supports only one monitor.

regs

https://en.wikichip.org/wiki/risc-v/registers

• C col: 3-bit compressed encoding
• Last col: save by caller or callee

Cache Parameters

2022.intel64_opt.pdf

搜索Cache Parameters可搜到各个架构的cache参数

caller/callee reg

x86_64-abi.pdf: Figure 3.4

x86-64-linux callee saved regs:

%rbx, %rbp, %r12-r15

conditinal code

2018.intel64.pdf: Volume 1: Appendix B: Table B-1

rflags/eflags

2020.amd64.pdf: 3.1.4

// 11           | Overflow  Direction
// 10..76.4.2.0 | Sign      Zero
// OD  SZ A P C | Auxiliary Parity
//              | Carry
pushf // get
popf  // set

regs ext

2020.amd64.pdf: 3.1.2

• byte(8) & word(16) oprs not modify high 56 or 48 bits
• dword(32) oprs zero-extended to 64 bits.

legacy encode

2020.amd64.pdf: Figure 1-2

2018.intel64.pdf: Figure 2-1

ext encode

2020.amd64.pdf: Figure 1-2

page size

2020.amd64.pdf: Table 5-1

• PAE: Physical-Address Extensions
• PSE: Page-Size Extensions
• PDPE:
• PDE

mnemonic syntax

2020.amd64.pdf: Volume 3: 2.5.1

        ADDPD xmm1, xmm2/mem128
        ──┬── ──┬─  ───────┬───
Mnemonic ─┘     │          │
                └────────┐ │
First Source Operand    ─┘ │
and Destination Operand    │
                           │
Second Source Operand ─────┘

opcode syntax

2020.amd64.pdf: Volume 3: 2.5.2

2018.intel64.pdf: Volume 2: 3.1.1.1

modrm

2020.amd64.pdf: Table 1-10

ModRM = mod[2] : reg[3] : r/m[3]

M: MMX, X: XMM, Y: YMM

sib

2020.amd64.pdf: Table 1-12

SIB = scale[2] : index[3] : base[3]

scale = 2^(SIB.scale)

mem opr

• Seg Selector: 16
• Offset (or Linear Addr): 32/64

mem opr: seg

2018.intel64.pdf: Table 3-5

Default Segment Selection

mem opr: off

2018.intel64.pdf: Table 3-5

Offset =
  Base  + (Index * Scale) + Displacement
  +- -+   +- -+     +-+      +------+
  |eax|   |eax|     |1|      |None  |
  |ebx|   |ebx|     |2|      |8-bit |
  |ecx|   |ecx|     |4|      |16-bit|
  |edx| + |edx|  *  |8|   +  |32-bit|
  |esp|   |ebp|     | |      |      |
  |ebp|   |esi|     | |      |      |
  |esi|   |edi|     | |      |      |
  |edi|   |   |     | |      |      |
  +- -+   +---+     +-+      +------+

seg regs

Kernel: FS and GS

• 32-bit mode
  • 6 seg regs, support seg limit
• 64-bit mode
  • C/S/D/ES are ignored, base addr is 0
  • FS: Thread Local Storage(TLS)
  • GS: use freely by app

Read and write from user space

• syscall: arch_prctl()
• FSGSBASE inst family (introduced by Ivy Bridge)

Addressing

• compiler: __seg_fs, __seg_gs
• assembly: mov %fs:offset, %reg, mov %reg, %fs:offset