zip -Z store -r  myfolder.zip myfolder

# decompress filename.tar.xx
tar xvf archive.tar.xz
# GNU tar recognizes the format by itself!

date=$(date '+%Y%m%d_%H%M%S')

SQL_TEXT="$(IFS=''; cat ~/dump/tbl1.sql)"
mysql -h 127.0.0.1 -e "${SQL_TEXT}"

SCRIPT_DIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" &> /dev/null && pwd )"

cp GIT_REPO/*  target_dir/

cp -u -r /home/peter/dst/* .

find . -path ./vendor -prune -false -o -name '*.go'`

find /usr/local/bin -type f -executable -exec sh -c 'test "$(head -c 2 "$1")" != "#!"' sh {} \; -print

find . -type d  -exec  chmod +x {} \;

find . -name '*_test.go' -exec grep -Hn 127.0.0.1 {} \;

find . -name '*_test.go' -exec grep -Hn [golang.org/x](http://golang.org/x)  {}\;

find . -name '*.go' -exec grep --color -Hn "TODO:" {} \;

find . -name '*.[ch]' -exec grep --color -Hn 'struct page {' {} \;

grep "\.[ch]$" source_index.txt

## find TODO in code repo, ignore the binary files
grep --binary-files=without-match -nr "TODO:" .

## find boost:: and std:: usage in code base
## extract value using grep
find .  -name "*.[hc]*" |xargs grep -Poh "\Kstd::\w+" {}  |sort |uniq -c |sort -h > ~/tmp/cpp_std.txt

find .  -name "*.[hc]*" |xargs grep -Poh "\Kboost::\w+" {}  |sort |uniq -c |sort -h > ~/tmp/cpp_boost.txt

grep:
    -o Print only the matched (non-empty) parts of a matching line, with each such part on a separate output line.
	-h Suppress the prefixing of file names on output.

	## mysql
    109 std::list
    110 std::cerr
    110 std::make_pair
    149 std::min
    151 std::nothrow
    181 std::swap
    202 std::map
    226 std::pair
    228 std::ostream
    251 std::endl
    341 std::size_t
    529 std::cout
   1008 std::vector
   3723 std::string
   ...
     50 boost::range_iterator
     90 boost::end
     93 boost::begin
    248 boost::geometry

du -h --max-depth=1 | sort -h

cloc  --not-match-f=".*_test.go" src/database/sql
Language                     files          blank        comment           code
-------------------------------------------------------------------------------
Go                               5            500           1472           3014


cloc  --match-f=".*_test.go" src/database/sql
Language                     files          blank        comment           code
-------------------------------------------------------------------------------
Go                               7            848            449           5721

dpkg -L mysql-community-server |grep -E '/s?bin/'

## curl 100 times, and write the results line by line

for i in {1..100}; do curl -s http://34.69.165.177/; echo '' ;done > result.txt

for f in *.sql; do (cat "${f}"; echo) >> all.txt; done

for dt in 2022-07-05 2022-07-06 2022-07-07 2022-07-08 2022-07-09 2022-07-10; do echo $dt; done

find somedir -type f -exec md5sum {} \; | sort -k 2 | md5sum

aws dynamodb list-tables | jq '.TableNames[]' > /tmp/dynamo_tables_test.txt

## xargs and dump files with parameterized file name
cat /tmp/dynamo_tables_test.txt | xargs -I{} sh -c 'aws dynamodb update-table --table-name="$1" --billing-mode PAY_PER_REQUEST > "$1.json"' -- {}

## parse environment variables
sed -z 's/$/\n/' /proc/4185/environ |grep -a GO
cat /proc/1/environ |tr '\0' '\n'
cat /proc/1/cmdline |tr '\0' '\n'
strings /proc/1/environ

## filter lines by keyword(/struct/!d) and keep the second line(2p)
sudo cat /proc/slabinfo |sed -e '2p' -e '/struct/!d'

redis-cli -h 127.0.0.1 -p 6379 client list >/tmp/clients.txt
# id=474958 addr=10.0.66.226:46704 fd=14 name= age=554798 idle=1 flags=N db=0 sub=0 psub=0 multi=-1 qbuf=0 qbuf-free=0 obl=0 oll=0 omem=0 events=rcmd=ping
# id=474959 addr=10.0.66.226:46699 fd=23 name= age=554798 idle=1 flags=N db=0 sub=0 psub=0 multi=-1 qbuf=0 qbuf-free=0 obl=0 oll=0 omem=0 events=rcmd=ping

awk '{print $2}' /tmp/clients.txt | sed -n 's/addr=\([0-9.]*\):.*/\1/p' | sort |uniq -c
 2 10.0.66.226

$ netstat -anp |grep  chia |grep LISTEN |awk '{ print $7 }' |sort |uniq | awk 'BEGIN { FS = "/" } { print $2}'
chia_daemon
chia_wallet
chia_full_nod
chia_farmer
chia_harveste

lsmod | awk '{if ($3 != 0) print $1, $2, $3, $4}'

# filter mysql slow query log
grep Rows_examined mysql-slowquery.log |awk '{ print $9}' |sort -h |less

find . -printf '%s %p\n'| sort -nr | head -10

'before'"$variable"'after'
'before'"'"'after'
'before'\''after'

# ${parameter/pattern/string}
# (https://www.gnu.org/software/bash/manual/bash.html#Shell-Parameter-Expansion)
# If pattern begins with ‘/’, all matches of pattern are replaced with string.
IP=10.0.2.15

echo ${IP/\./_}
10_0.2.15

echo ${IP//\./_}
10_0_2_15

for i in ./docdb_* ; do mv "$i" "${i/blog_q2/p2p_q1}" ; done
for i in ./*.mp3 ; do mv "$i" "${i/ /_}" ; done

diff -u working/slang.c latest/slang.c > 1.patch
patch -u prod/other.c -i 1.patch

## turn off bash history:
unset HISTFILE
#or
set +o history

## turn on bash history
set -o history

docker logs aaasdas9c356 > docker.log 2>&1

journalctl --since "2020-01-02 05:17"

## system log 15 min before. (in `/var/logs/messages` before)
journalctl -k --since "10min ago”

## watch logs in directory
## ignored lines started with `==>` and empty lines
tail -f ./log | grep -v --line-buffered -e "^==> . <==$" | grep -v -e '^$'

da=$(date +'%s.%3N'); XXX; db=$(date +'%s.%3N'); echo "$(echo "($db - $da)"|bc)"

while [ 1 = 1 ];do da=$(date +'%s.%3N');mysql --defaults-file=./my.cnf -D windmills_large -e "insert into windmills_test select null,uuid,millid,kwatts_s,date,location,active,time,strrecordtype from windmills4 limit 1;" -e "select count(*) from windmills_large.windmills_test;" > /dev/null;db=$(date +'%s.%3N'); echo "$(echo "($db - $da)"|bc)";sleep 1;done

$ python2 -m SimpleHTTPServer 8000
$ python3 -m http.server

# dig using specified DNS server
dig @8.8.8.8 tinyurl.com

# clean DNS cache
sudo systemd-resolve --flush-caches

$ sudo lsof -nP -i4TCP:1080 -sTCP:LISTEN
$ sudo lsof -nP -i4TCP:1080 -sTCP:ESTABLISHED
$ sudo lsof -iTCP -sTCP:LISTEN -n -P

# -a means AND in lsof
$ sudo lsof -itcp -a -p "1280595"

$ sudo tcpdump -i all host 127.0.0.1 and port 1080 -w cap1.pcap

# Bring wlan0 online
ip link set wlan0 up

# Bring wlan0 offline
ip link set wlan0 down

cat /sys/class/net/enp4s0/speed
ethtool enp4s0

# server
iperf3 -s

# client
iperf3 -c 192.168.2.1

# listen on the remote side, and forward connection to the local side
ssh -p 22 -qngfNTR 8082:localhost:8080 dev2

ssh -tt -i  ~/.ssh/ssh1.pem user1@JUMP-SERVER \
'ssh -tt -i ssh2.pem  user2@INTERNAL-SERVER '"'"'tmux -L session1  attach'"'"''

> hping -S -p 80 www.sunet.se
HPING www.sunet.se (eth0 192.36.171.155): S set, 40 headers + 0 data bytes
len=46 ip=192.36.171.155 ttl=59 DF id=0 sport=80 flags=SA seq=0 win=5840 rtt=0.7 ms

nmap -sV 192.168.28.0/24 | grep -wE '(scan report|ssh)'

## check open port of host
nmap 192.168.28.14

$ swapon --show
NAME       TYPE SIZE USED PRIO
/.swapfile file   4G 1.5G   -2

$ ll /.swapfile
-rw------- 1 root root 4294967296 Aug 18  2022 /.swapfile


$ sudo fallocate -l 32G /swapfile
$ sudo mkswap /swapfile
$ sudo swapon /swapfile

$ swapon --show
NAME       TYPE SIZE USED PRIO
/.swapfile file   4G 1.5G   -2
/swapfile  file  32G   0B   -3

$ mount -o loop,offset=63963136 RetroPie_2017_8_29_rom.img /mnt/2

# find offset if multiple partition exists.
$ parted RetroPie_2017_8_29_rom.img
Disk /home/pi/RetroPie_2017_8_29_rom.img: 3276MB
Sector size (logical/physical): 512B/512B
Partition Table: msdos
Disk Flags:

Number  Start   End     Size    Type     File system  Flags
 1      4194kB  64.0MB  59.8MB  primary  fat16        lba
 2      64.0MB  3275MB  3211MB  primary  ext4

(parted) u
Unit?  [compact]? B
(parted) print
Model:  (file)
Disk /home/pi/RetroPie_2017_8_29_rom.img: 3275999744B
Sector size (logical/physical): 512B/512B
Partition Table: msdos
Disk Flags:

Number  Start      End          Size         Type     File system  Flags
 1      4194304B   63963135B    59768832B    primary  fat16        lba
 2      63963136B  3274702847B  3210739712B  primary  ext4

/dev/xvdh1 /myfs xfs defaults,nofail,x-systemd.device-timeout=30 0 0

checking for protobuf... no
configure: error: Package requirements (protobuf) were not met:

No package 'protobuf' found

Consider adjusting the PKG_CONFIG_PATH environment variable if you
installed software in a non-standard prefix.

Alternatively, you may set the environment variables protobuf_CFLAGS
and protobuf_LIBS to avoid the need to call pkg-config.
See the pkg-config man page for more details.

compgen -c

## edit /etc/default/grub
GRUB_GFXMODE=1024x768x32
GRUB_GFXPAYLOAD_LINUX=keep
GRUB_DEFAULT="2"

## sudo update-grub2

cat ~/.ssh/id_rsa.pub | xclip -selection c

spd-say -t female3 "Good morning, Jimmy”