# 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

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

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

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

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

# 等价于cd $OLDPATH
cd -

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

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

set -o errexit

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

COMMAND <<InputComesFromHERE
# ...
InputComesFromHERE

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

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

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

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

set -o xtrace

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

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

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

-DCMAKE_EXPORT_COMPILE_COMMANDS=1

docker ps -as

docker images -a

docker system prune

docker ps -aq | xargs docker rm

docker images -aq | xargs docker rmi

docker rm <containers>

docker rmi <images>

docker stop <containers>

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

podman unshare
podman image mount <image>

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

--cap-add=SYS_PTRACE

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

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

df -h

du -sBM * | sort -n

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

magika

fc-list
fc-scan

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

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

qemu-img resize <.qcow2> +2G

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

service linux start

gcc -Q --help=target

gcc -march=native -Q --help=target

#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;
}

#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;
}

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

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

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

cd src
doxygen

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

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

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

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

# 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>

git clone git://10.90.50.99/<REPO>

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

git ls-remote --tags <repo>

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

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

git-quick-stats

git diff > <xxx.patch>

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

# add a linked worktree in ../folder
git worktree add ../<folder> [<commit>]
# its ok to directly remove folder, then
git worktree prune

grep -l

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

tailscale up --force-reauth --reset

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

sudo docker exec headscale headscale --help

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

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

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

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

make defconfig && make

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

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

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

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

modinfo <mod>

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

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

lli <file.ll/bc>

# a rule
target … : prerequisites …
    recipe
    …

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

define \n


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

$(wildcard pictures/*.drawio)

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

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

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

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

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

remake --targets

<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>

sudo nethogs

host <domain name>

nmap 192.168.1.0/24

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

# 列支持的语言
tesseract --list-langs

# 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>

pandoc --list-highlight-languages

pandoc -D <FORMAT>

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

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

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

perldoc perlrun

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

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

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

apk info -L <pkg>

dpkg-deb -c <package_name.deb>

dpkg-query -L <package_name>

apt-file list <package_name>

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

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

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

./OpenCore-Boot.sh

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

left aligned

!
:::

<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>

::: {style="width:1000px; height: 400px; display:inline-block; text-align:center;"}
:::: {style="transform: scale(2); transform-origin: left top;"}
``` {.include}
./plotly/bt_perf-mini.html
```
::::
:::

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

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

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

rustup show

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

scons -c

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

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

sed '/<pattern>/Q 1'

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

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

// 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,
];



}

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

ssh -L <localPort>:<remoteURL>:<remotePort> -N -T <sshTarget>

ssh -L 8890:localhost:8889 -N -T tso.rsp3
# then change switchyomega to SSH_L preset

ssh -Y

man systemd.unit

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

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

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

#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

[Unit]
Description=Swapon

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

[Service]
ExecStart=swapon /swapfile

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

ffmpeg -i input.avi -c:v libx264 -crf 18 -preset veryslow -c:a copy out.mp4

parallel -j2 ffmpeg -i {} -c:v libx264 -crf 18 -preset veryslow -c:a copy {.}.x264.18.mp4 ::: *.MP4

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

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

DISPLAY=:2 <command>

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

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

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

yarn global add node_module

yarn global bin

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

dgen <path>

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

gtk-launch <xxx.desktop>

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

kitty +kitten ssh myserver

kitty +kitten ssh -J jump_server destination_server

# 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>

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

inkscape \
  --without-gui \
  --file=input.pdf \
  --export-plain-svg=output.svg

pdftotext -q <pdf>

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

adduser xieby1
usermod -aG sudo xieby1

sort -s -n -k 1,1

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

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

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

::: {style="width:1000px; height: 400px; display:inline-block; text-align:center;"}
:::: {style="transform: scale(2); transform-origin: left top;"}
``` {.include}
./plotly/bt_perf-mini.html
```
::::
:::

::: {style="zoom: 200%;"}
...
:::

# no suffix .tex/.bib
checkcites Thesis

import pdb
pdb.set_trace()

dir()
vars()

<code needed to be ignored> # type: ignore

# pyrightconfig.json
{
  reportGeneralTypeIssues = false,
}

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

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

:h compl-vim

vim -V9myVim.log

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

ls <$VIMRUNTIME>/syntax/

:call GitWipSave()

# list all DIR/FILE
zellij setup --check

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

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

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

nix-store -qR

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

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

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

{
  allowUnfree = true;
}

nix-env -q --out-path

nix-shell
. $stdenv/setup

nix-build -K <drv>

nix-build '<nixpkgs>' -A xxx

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

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

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

sudo nix-collect-garbage -d

nix-collect-garbage -d

# list
home-manager generations
# clean generations beyond 1 day
home-manager expire-generations -1day

find -L . -name . -o -type d -prune -o -type l -exec rm {} +

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

cd /nix/var/nix/gcroots/auto
for i in *; do if [[ $(readlink $i) =~ /result ]]; then echo $i; echo $(readlink $i); fi; done

cd /nix/var/nix/gcroots/auto
for i in *; do if [[ $(readlink $i) =~ /.direnv/ ]]; then echo $i; echo $(readlink $i); fi; done

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

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

hardeningDisable = ["formt"];
hardeningDisable = ["all"];

export NIX_HARDENING_ENABLE=""

echo "use nix" >> .envrc
direnv allow

nurl [OPTIONS] [URL] [REV]

nix-prefetch-url

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

nix-prefetch-url --unpack

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

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

nix derivation show <.drv>

pkgs = import <nixpkgs> {}

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

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

nix-version --hash

sshd-start

home-manager option <OPTION>

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

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

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

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

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

patchShebangs <path>

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

# nix built-in
nix bundle nixpkgs#hello
nix bundle --expr '(import <nixpkgs> {}).hello'

# github 465 start
nix-bundle hello /bin/hello

nix-tree </nix/store/path>

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

lib.lowPrio <pkg>

nix-locate 'bin/hello'

:?

:e <expr>

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

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

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

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