url=https://raw.githubusercontent.com/fzinfz/scripts/master/init.sh # alias & functions
source /dev/stdin <<< "$(curl -sS $url)"
​
set
    -x                      debug
    -T                      If  set, any traps on DEBUG and RETURN are inherited
    -o functrace/errtrace
​
shopt [-pqsu] [-o] [optname …]
    -s: Enable (set) each optname.
    -u: Disable (unset) each optname.
​
shopt -s expand_aliases     # when the shell is not interactive
alias foo='...'
​
0: stdin; 1: stdout; 2: stderr              # File descriptor
2>&1 >/dev/null
&>/dev/null
ssh-add 2>/dev/null

ctrl+b x -> kill pane   # /usr/share/doc/tmux/examples/screen-keys.conf
cat /usr/share/doc/tmux/examples/screen-keys.conf | grep '\bbind \w'

ls -R -l /etc/rc*
​
ls -l /usr/lib/systemd      # check `systemd` page for more
ls -l /usr/share/upstart    # last release 2014; 3 years ago
ls -l /etc/init.d           # SysV init
​
cat /etc/modules-load.d/*
​
apt install systemd-sysv    # make link: /sbin/init -> /lib/systemd/systemd
​
vi ~/.bash_profile          # login shells
vi ~/.bashrc                # non-login shells

1    Catchall for general errors
2    Misuse of shell builtins
126    Command invoked cannot execute
127    "command not found"    illegal_command    Possible problem with $PATH or a typo
128+n    Fatal error signal "n"    
    kill -9 $PPID of script    $? returns 137 (128 + 9)
130    Script terminated by Control-C

0       Emergency: system is unusable
1       Alert: action must be taken immediately
2       Critical: critical conditions
3       Error: error conditions
4       Warning: warning conditions
5       Notice: normal but significant condition
6       Informational: informational messages
7       Debug: debug-level messages

kill -l
1) SIGHUP       2) SIGINT       3) SIGQUIT      4) SIGILL       5) SIGTRAP
6) SIGABRT      7) SIGBUS       8) SIGFPE       9) SIGKILL ... 64) SIGRTMAX

pkill -KILL -u {username}

pip install glances[action,browser,cloud,cpuinfo,chart,docker,export,folders,gpu,ip,raid,snmp,web,wifi]

sudo adduser foobar www-data
sudo usermod -a -G ftp tony

echo user:pwd | chpasswd

sudo visudo
    root    ALL=(ALL) ALL # {terminals}=({users}) {commands}
    %supergroup  ALL=(ALL) NOPASSWD:ALL

chown -h myuser:mygroup mysymbolic

subscription-manager register
subscription-manager attach --auto
subscription-manager repos --enable rhel-7-server-optional-rpms
subscription-manager repos --enable rhel-7-server-extras-rpms
yum install epel-release
rm -f /var/run/yum.pid <PID> && yum remove PackageKit
​
yum-config-manager --disable c7-media
yum --nogpgcheck localinstall xx.rpm
​
### EPEL
http://elrepo.org/tiki/tiki-index.php
​
rpm --import https://www.elrepo.org/RPM-GPG-KEY-elrepo.org
rpm -Uvh http://www.elrepo.org/elrepo-release-7.0-3.el7.elrepo.noarch.rpm
yum install yum-plugin-fastestmirror
yum --enablerepo=elrepo-kernel install kernel-ml

# https://mirror.tuna.tsinghua.edu.cn/help/ubuntu/
deb https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ xenial main restricted universe multiverse

deb http://deb.debian.org/debian/ experimental main contrib non-free
deb https://mirrors.tuna.tsinghua.edu.cn/debian stretch main contrib non-free

dpkg --get-selections   # list installed

apt-get install linux-base -t jessie-backports
apt-cache search linux-image | grep linux-image-4
apt install linux-image-4.10.0-9-generic linux-image-extra-4.10.0-9-generic
​
apt show linux-image-extra-4.10*
​
apt-get install --only-upgrade docker-engine
​
apt policy docker-ce | head -n 20
​
apt-get autoclean
apt list --installed
​
rm -r /var/lib/apt/lists/*

grub2-mkconfig -o /boot/grub2/grub.cfg
awk -F\' '/menuentry / {print $2}' /boot/grub/grub.cfg
grub2-set-default 'CentOS Linux (4.9.0-rc8-amd64) 7 (Core)'
grub2-editenv list

sudo add-apt-repository ppa:danielrichter2007/grub-customizer
sudo apt-get update
sudo apt-get install grub-customizer

sudo add-apt-repository ppa:yannubuntu/boot-repair
sudo apt-get update
sudo apt-get install -y boot-repair && boot-repair

    sysbench --test=cpu --cpu-max-prime=20000 --num-threads=32 run
​
    wget http://www.numberworld.org/y-cruncher/y-cruncher%20v0.7.1.9466-static.tar.gz
    tar zxvf y-cruncher\ v0.7.1.9466-static.tar.gz

ssh -L 9000:public.com:80   # visit local:9000 -> public.com:80
ssh -R 9000:localhost:3000  # visit remote:9000 -> local:3000, "GatewayPorts yes" in sshd_config
    -nNT -L ...   # port forwarding only, no shell

wget -O diff_name.zip http://...

curl -O http://...
curl -o diff_name.zip http://
​
curl -sSL $1
​
  -f, --fail          Fail silently (no output at all) on HTTP errors (H)
  -s, --silent        Silent mode (don't output anything)
  -S, --show-error    Show error. With -s, make curl show errors when they occur
  -L, --location      Follow redirects (H)
  -o, --output FILE   Write to FILE instead of stdout
  -O, --remote-name   Write output to a file named as the remote file

apt-get install mlocate
updatedb
locate -S
lsof -p <PID>
​
ls --help | grep -E '[-][tr]\b'
-r, --reverse              reverse order while sorting
                            extension -X, size -S, time -t, version -v
-t                         sort by modification time, newest first
​
mkdir -p /not/existing/folder
​
cat > file <<'EOL'
EOL
​
ncdu --exclude='/root/data/*' /
​
du -hcd 2  / | more
du -a / | sort -n -r | head -n 20
​
ls -1 $PWD | wc -l  # count files
​
file /bin/ps
ldd /bin/ps

find /home -iname tecmint.txt
find $1 -iname $2
# find . ! -readable / -writable / -executabl
# find . ! -perm -g=w
​
find -regextype posix-extended -regex ".*[.](py|sh)" -exec chmod +x {} \;

grep --color=auto -rn -P "${regex}" ${path}
# -r, --recursive           like --directories=recurse
# -n, --line-number         print line number with output lines
# -P, --perl-regexp         PATTERN is a Perl regular expression

gunzip file.gz
​
tar -czvf name-of-archive.tar.gz /path/to/directory-or-file # Compress
​
tar -tvf my-data.tar.gz '*.py'
​
tar -zxvf toExtract.tar.gz
tar -xvf {tarball.tar} {special_file} -C /target/directory
​
tar -cf archive.tar foo bar  # Create archive.tar from files foo and bar.
tar -tvf archive.tar         # List all files in archive.tar verbosely.
tar -xf archive.tar          # Extract all files from archive.tar.
    -t, --list                 list the contents of an archive
    -j, --bzip2                filter the archive through bzip2
    -c, --create               create a new archive    
    -x, --extract, --get       extract files from an archive    
    -z, --gzip, --gunzip, --ungzip   filter the archive through gzip
    -v, --verbose              verbosely list files processed
    -f, --file=ARCHIVE         use archive file or device ARCHIVE
​
zip [options] zipfile files_list
    -r   recurse into directories
    -x   exclude the following names
    -v   verbose operation/print version info
​
    -m   move into zipfile (delete OS files) !!
    -d   delete entries in zipfile !!!
    -u   update: only changed or new files
​
 xz --decompress file.xz # -dgrub

rsync -aP -e "ssh -p $3" $1 root@$2
​
rsync -aP  /root/_bin root@remote:/root
rsync -aP -e "ssh -p 10220" /local root@remote:/dir   --remove-source-files
    -v, --verbose               increase verbosity
    -a, --archive               archive mode; equals -rlptgoD (no -H,-A,-X)
        --no-OPTION             turn off an implied OPTION (e.g. --no-D)
    -r, --recursive             recurse into directories
    -l, --links                 copy symlinks as symlinks
    -p, --perms                 preserve permissions
    -o, --owner                 preserve owner (super-user only)
    -g, --group                 preserve group
    -D                          same as --devices --specials
    -t, --times                 preserve modification times
    -S, --sparse                handle sparse files efficiently
    -e, --rsh=COMMAND           specify the remote shell to use
        --partial               keep partially transferred files
        --partial-dir=DIR       put a partially transferred file into DIR
    -z, --compress              compress file data during the transfer
        --progress              show progress during transfer
    -P                          same as --partial --progress

history | cut -c 8-
  -a    append history lines from this session to the history file  ~/.bash_history    

sudo timedatectl set-ntp true
TZ='Asia/Shanghai'; export TZ

apt-get install  xfonts-base

getenforce
semanage port -a -t mongod_port_t -p tcp 27017

cat openwrt-lantiq-ram-u-boot.asc > /dev/ttyUSB0
screen /dev/ttyUSB0 115200
picocom -b 115200 /dev/ttyUSB0

vi /etc/environment
systemctl restart snapd

echo export JAVA_HOME="/usr/lib/jvm/java-1.8.0-openjdk" >> /etc/profile

apt install -y locales-all
locale -a
dpkg-reconfigure locales
​
yum grouplist chinese-support
​
sudo apt-get install -y ttf-wqy-microhei  #文泉驿-微米黑
sudo apt-get install -y ttf-wqy-zenhei  #文泉驿-正黑
sudo apt-get install -y xfonts-wqy #文泉驿-点阵宋体

chromium --no-sandbox # start as root

export http_proxy=http://proxy_ip:1080
export https_proxy=http://proxy_ip:1080
​
sudo apt install -y proxychains
vi /etc/proxychains.conf

git clone https://github.com/hoytech/vmtouch.git
cd vmtouch && make && sudo make install
​
Discovering which files your OS is caching
Telling the OS to cache or evict certain files or regions of files
Locking files into memory so the OS won't evict them
Preserving virtual memory profile when failing over servers
Keeping a "hot-standby" file-server
Plotting filesystem cache usage over time
Maintaining "soft quotas" of cache usage
Speeding up batch/cron jobs

ethtool enp1s0  | grep Wake-on
​
p (PHY activity)
u (unicast activity)
m (multicast activity)
b (broadcast activity)
g (magic packet activity) *
a (ARP activity)
d (disabled)

getconf LONG_BIT

cat /proc/cpuinfo  | grep -P 'processor|physical id|core id|^$'
​
pip install walnut    # pretty print
for c in sorted([ ( int(c['processor']), int(c['physical id']), int(c['core id']) ) for c in cpu.dict().values()]): print c

dpkg -l amdgpu-pro
glxinfo | grep direct
GALLIUM_HUD=help glxgears

sudo apt install ocl-icd-opencl-dev