# cheatsheets

**Repository Path**: peliu/cheatsheets

## Basic Information

- **Project Name**: cheatsheets
- **Description**: No description available
- **Primary Language**: Unknown
- **License**: Not specified
- **Default Branch**: master
- **Homepage**: None
- **GVP Project**: No

## Statistics

- **Stars**: 0
- **Forks**: 0
- **Created**: 2020-05-26
- **Last Updated**: 2026-09-28

## Categories & Tags

**Categories**: Uncategorized

**Tags**: None

## README

# cheatsheets

cheatsheets

# bash & linux

```bash
#!/bin/bash
set -xeuo pipefail

# http://ezprompt.net/ a tool for PS1 settings.
PS1="\[\e[35m\]\j\s\v \D{%Y-%m-%dT%H:%M:%S%z} \u@\h:\w/\[\e[m\]"
alias ls='ls -atlrh --color=auto'
bash -c "ls -atlrh /tmp"
readlink -f file.txt # show full path of a file
ls -atlrhd name*tag
ls -S # Sort by size
mkdir -p /dir1/dir2/{dira,dirb}

#Cp mutiple files to a directory(bash only)
cp /home/ankur/folder/{file1,file2} /home/ankur/dest
cp -t dest_dir file1 file2 file3

for i in {1..150} ; do echo "$i"; sleep 1; done
for i in $(seq 1 10) ; do echo "aaa${i}aaa"; done
for i in aaa bbb ccc ; do echo $i; done
for i in [aaa bbb ccc] ; do echo $i; done
for h in `cat containers.txt`; do echo $h; done
for d in ./*;do [[ -f "$d" ]] && echo "${d##./}"; done
for d in ./*;do [[ -d "$d" ]] && e="${d##./}" && echo $e; done

while true; do printf .; sleep 5;done
while [[ true ]]; do ls -atlrh; sleep 5; done
mount -t glusterfs -o acl ip:/export_path /local_path/mnt
mount -t glusterfs -o ro ip:/export_path /local_path/mnt # readonly
mount -t nfs ip:/export_path /local_path/mnt

env TZ=Asia/Shanghai date +"%Y-%m-%d %H:%M:%S %z"
date +P%Y%m%d%H%M%S%N%z | sed "s/+/E/g" | sed "s/-/W/g"

ps -eo pid,comm,lstart,etime,time,args | grep tomcat


# Show line numbers
nl file.txt
cat -b file.txt # Same as above cmd
cat -n file.txt

# same result, pipe or <()
nl <(cat *.tmp | sed '/^NAME/i\\' )
cat *.tmp | sed -n '/^LAST/, /^NAME/p' | sed '/^LAST/i\\' | nl

# Cmd to Create & Append to a file from command line command. Convenint for shell scripts usage
cat <<EOF > tmp.txt
file lines
EOF
# Similar as above. Keep indent format & append lines to existed file
cat <<-EOF >> tmp.txt
file lines
EOF


uuidgen
cmd1 && cmd2 && cmd3
cmd1 || cmd2 || cmd3

echo "aaabbbccc" | base64
echo "YWFhYmJiY2NjCg==" | base64 --decode

ln -s [OPTIONS] (target)FILE LINK
# change own for link itself instead of the link target.
chown -h user1 jakarta
# show file full path. Show link target path(not link file path)
readlink -f filename
echo $PWD/20200908182742UTC.sql

nohup myprogram </dev/null >myprogram.log 2>&1 &

# curl with user:pwd
curl -u username:password http://example.com
# curl upload file
curl -i -X PUT -H "Content-Type: multipart/form-data" -F "apivarname=@locfilepath" -vvv http://localhost:8080/api/v1/method
# http://host:port(8080/8081/...)/swagger-ui.html
# curl output and pipe redirect
curl -X PUT http://localhost:8080/api/v1/method -o std.out > out.std 2>&1 &
curl -g -G --data-urlencode 'match[]={label=~"label1|label2"}' http://host:port/federate > out.prom
curl -ss http://google.com > temp.html 2>&1 # Don't show process bar. -s options: silent. But double ss for versions compatible & all output(err, out) so ending with 2>&1.
curl -k -u user:pass -H "Content-Type:application/json" -H 'Authorization:bearer' -X POST -d '{"Id":"12330245","visitTimes":1,"docType":"sanwen","docId":"36e5854f5f0e4f80b7ccc6c52c063243"}' https://host:443/invoke/api/v2/method
curl -k -u user:pass -H "Content-Type:application/json" -H 'Authorization:bearer' -X POST -d '@my.json' https://host:443/invoke/api/v2/method

# Install package from source without root/sudo
wget http://sourceforge.net/projects/sshpass/files/latest/download -O sshpass.tar.gz
tar -xvf sshpass.tar.gz
cd sshpass-1.06/
./configure --help
./configure --prefix='/home/dir/user/sshpass/bin'
make
make install

# ssh&scp usage
alias ssh='ssh -q -o "UserKnownHostsFile=/dev/null" -o "StrictHostKeyChecking=no" -o "ForwardAgent=yes" -o "TCPKeepAlive=yes" -o "ServerAliveInterval=30"'
ssh -vvv -i private_key user@host # Verbose for debug. max v: 3.
ssh -vC2qTnNf -D 6502 -i ~/.ssh/private.pem user@host # tunnel
scp -o "ForwardAgent=yes" -i id_rsa -F config -oProxyJump=jmp user@host:/tmp/file locfile
sshpass -e scp -J jumphost1,jumphost2 -F config -q -o "UserKnownHostsFile=/dev/null" -o "StrictHostKeyChecking=no" -o "ForwardAgent=yes" deployment.yaml user@host:/directories/
scp -i private_key_path -oProxyJump=jum user@host:remote_file_path local_path
sshpass -f filepath ssh -J jumphost1,jumphost2 -/F config -q -o "UserKnownHostsFile=/dev/null" -o "StrictHostKeyChecking=no" -o "ForwardAgent=yes" user@host 'cmd'
# Change the default setting for ssh login. Enable password access
sed -i 's/PasswordAuthentication no/PasswordAuthentication yes/g' /etc/selinux/config /etc/ssh/sshd_config
systemctl restart sshd
passwd

shellcheck scripts.sh

rsync -r --verbose --exclude 'exclude_pattern1' --exclude 'exclude_pattern2' source target
rsync -av --progress sourcefolder /destinationfolder --exclude thefoldertoexclude
rsync -av --progress sourcefolder /destinationfolder --exclude thefoldertoexclude --exclude anotherfoldertoexclude

du -hs * | sort -hr

# list subdirectory names in file
# https://askubuntu.com/questions/994602/how-to-write-out-all-directory-names-into-a-text-file
# Improving you current code, this command should be helpful:
for d in ./*;do [[ -d "$d" ]] && echo "$d" >> dir.txt; done
# To remove the ./ from the output:
for d in ./*;do [[ -d "$d" ]] && echo "${d##./}" >> dir.txt; done
for d in ./*;do [[ -f "$d" ]] && echo "${d##./}"; done
for d in ./*;do [[ -d "$d" ]] && echo "${d##./}"; done
for d in ./*;do [[ -d "$d" ]] && e="${d##./}" && zip -re -Ppasswd $e $e/ ; done
# Show the items of the file
for d in $(cat dir.txt); do echo $d; done
for d in $(cat dir.txt); do zip -re $d $d/; done
for d in $(cat dir.txt); do zip -re -Ppasswd $d $d/; done

# https://stackoverflow.com/questions/2059794/what-is-the-meaning-of-the-0-syntax-with-variable-braces-and-hash-chara
# See the section on Substring removal in the Advanced Bash-Scripting Guide‡:
${string#substring}
# Deletes shortest match of substring from front of $string.
${string##substring}
# Deletes longest match of substring from front of $string.
# The substring may include a wildcard *, matching everything. The expression ${0##/*} prints the value of $0 unless it starts with a forward slash, in which case it prints nothing.
```

```bash
# In case 'sudo cat' meet with 'Permission denied' issue please switch to 'sudo tee'
sudo cat > /data/mysql/data_cnf/cnf/my.cnf << EOF
[mysqld]
ssl-ca=/var/lib/mysql/ca.pem
ssl-cert=/var/lib/mysql/server-cert.pem
ssl-key=/var/lib/mysql/server-key.pem
EOF
-bash: /data/mysql/data_cnf/cnf/my.cnf: Permission denied

# 'sudo tee' does not have this issue
sudo tee /data/mysql/data_cnf/cnf/my.cnf > /dev/null <<- EOF
[mysqld]
ssl-ca=/var/lib/mysql/ca.pem
ssl-cert=/var/lib/mysql/server-cert.pem
ssl-key=/var/lib/mysql/server-key.pem
EOF
```

## ssh config

```config
Host jmp
    Hostname host
    User logonuser
    IdentityFile ~/.ssh/id_rsa
    HostKeyAlgorithms=+ssh-dss
    ForwardAgent yes
    LogLevel error
    StrictHostKeyChecking no
    UserKnownHostsFile=/dev/null
    TCPKeepAlive yes
    ServerAliveInterval 30
```

## cursor movement

| Move by             | Forward | Backward |
| ------------------- | ------- | -------- |
| word                | M-f     | M-b      |
| line                | C-e     | C-a      |
| switch line/current | C-x C-x | C-x C-x  |

## delete characters

| del by | End/Forward | Begin/Backward |
| ------ | ----------- | -------------- |
| word   |             | M-Backspace    |
| char   | C-d         | Backspace      |
| space  |             | C-w            |
| line   | C-u         | C-k            |

## performance

```bash
vmstat 5 10
sar 1 3
mpstat 1 3 # same with sar?
```

# Network

```
nmap hostname # check which ports are opened on the host
```

## DNS

```bash
# https://www.hostinger.com/tutorials/how-to-use-the-dig-command-in-linux/
dig +answer +short hostname.corp.com
dig +answer +short -x ip.ip.ip.ip
dig hostinger.com +trace
https://www.cyberciti.biz/faq/linux-unix-dig-command-examples-usage-syntax/
dig Hostname
dig DomaiNameHere
dig @DNS-server-name Hostname
dig @DNS-server-name IPAddress
dig @DNS-server-name Hostname|IPAddress type
nslookup ip # find hostname from ip
nslookup hostname # find ip from hostname
```

[More](network.md)

# springboot

```bash
java -jar -Dspring.profiles.active=activeprofilename app.jar
```

# redis

```bash
redis-server redis.conf
redis-cli -c -p port -h host

# scan
scan 0
scan 17
sscan myset 0 match f*
scan 176 MATCH *11* COUNT 1000
SCAN 0 TYPE zset
hscan hash 0

docker run -it --rm redis redis-cli -h host -p 6379 # Just run it from commad line. It does NOT work to 'docker exec -it container_name sh' or 'docker run -it --rm image sh' to the container then run 'redis-cli -h host -p port'
```

# python

```bash
docker run -it --rm -it --entrypoint=/bin/sh --name py3alpine python:3.8.3-alpine3.11
docker run -it --rm -it --entrypoint=/bin/sh --name py2 python:2
```

```python
# pending...
```

# json

```bash
cat json.txt | python -m json.tool

yum install epel-release
yum install jq
cat json.txt | jd .
```