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ansible aptitude at awk aws curl conda cron date docker du fallocate find firewalld fpm git helm iptables jq kubectl lftp lvm mysql nc openssl pip postgresql python route rpm rsync screen sed setfacl ssh systemd tar tcpdump tmux uv vim wget yq yum zip misc

aptitude

aptitude update
aptitude upgrade
aptitude install krb5-multidev

# /etc/apt/sources.list
# http://archive.ubuntu.com/ubuntu/dists/
# http://old-releases.ubuntu.com/ubuntu/dists/

at

echo /opt/bin/run.py | at 5pm + 3 days

atq
at -c 1
atrm 1

awk

awk -F: '($3<1000){print $1}' /etc/passwd

aws ecr describe-repositories --output text | awk '($1~/^REPO/){print $NF}'
yarn application -list | awk '(NR>2){print $1}'

ss -4lntp | awk 'NR==1 {print $1"\t"$5} NR>1 {print $1"\t"$4"\t"$6}'

aws

$(aws ecr get-login --no-include-email --region ap-east-1 --registry-ids 857857857857)
$(aws ecr get-login --no-include-email --region ap-east-1)

docker_ecr_password=$(aws ecr get-login-password --region ap-east-1)
docker login --username AWS --password $docker_ecr_password 857857857857.dkr.ecr.ap-east-1.amazonaws.com

aws s3 ls --summarize --human-readable --recursive s3://bucket-name

# if not run as aws account b
aws s3 sync s3://account-a-bucket/folder/ s3://account-b-bucket/folder/ --acl bucket-owner-full-control

# if s3 vpc endpoints disabled
aws s3 sync s3://src-bucket/folder/ s3://dst-bucket/folder/ --source-region us-west-1 --region us-west-2

aws sts get-caller-identity

curl

curl -sL https://www.opscode.com/chef/install.sh | sudo bash

curl --fail -u username:password --upload-file heylinux-app.rpm http://nexus.heylinux.com/repository/devops/rpms/

curl --progress-bar -o /tmp/heylinux-app.rpm http://nexus.heylinux.com/repository/devops/rpms/heylinux-app.rpm

curl -XPUT -k -u 'username:password' 'https://service.heylinux.com/api/subject/' \
-H 'Content-Type: application/json' \
-d '{"key":"value"}'

curl -s -w "connect time: %{time_connect}s, time to first byte: %{time_starttransfer}s, \
total time: %{time_total}s, num connects: %{num_connects}, speed download: %{speed_download}bytes/s, \
speed upload: %{speed_upload}bytes/s, time prexfer: %{time_pretransfer}s \n" \
-o /dev/null https://blog.heylinux.com

curl --header "PRIVATE-TOKEN: <your_access_token>" \
"https://jihulab.com/api/v4/projects/857857/repository/files/folder%2Fpackage.tar/raw?ref=main" \
-o package.tar

conda

bash Miniconda3-latest-Linux-x86_64.sh -b -p /opt/miniconda

source /opt/miniconda/etc/profile.d/conda.sh

conda config --show channels
conda config --append channels conda-forge

conda create --name py312 python=3.12
conda activate py312

conda deactivate
conda remove --name my312 --all

conda search boto3
conda search | grep r-aws

conda install paramiko boto3
conda list | grep boto3

echo 'use_only_tar_bz2: true' >> ~/.condarc
conda install --download-only -c conda-forge s3fs==0.3.5

source /opt/miniconda/bin/activate pyvsgo

#!/opt/miniconda/envs/pyvsgo/bin/python

conda list -e > environment.txt
conda create --name pyvsgo --file environment.txt

cron

echo damonguo >> /etc/cron.allow

crontab -u damonguo -l
---
## minute hour day-of-month month day-of-week(0/7=sun)
##  0-59  0-23     1-31     1-12  0-7/mon,tue,wed,thu,fri,sat,sun
# OPS-857: run /opt/bin/run.py every 5 minutes and log all outputs and alert if fail
SHELL=/bin/bash
MAILTO="ops-alerts@heylinux.com"
*/5 * * * * ps aux | grep /opt/bin/run.py | grep -v grep || /opt/bin/run.py >> /opt/logs/run.out 2> >(tee -a /opt/logs/run.err >&2)

date

# ISO-8601
# 2025-12-22T10:03:07+08:00
date '+%Y-%m-%dT%H:%M:%S%:z'
date --iso-8601=seconds

docker

# override ENTRYPOINT and CMD in built image
    platform: linux/amd64
    entrypoint: ["sleep"]
    command: ["infinity"]
    restart: no

du

du -shc /path/to/dir/*
du -ah --max-depth 1 --exclude='proc' | sort -k2 | awk '($1 ~ /M|G|T/){print $1"\t"$2}'
du -ah --max-depth 1 --exclude='proc' | awk '($1 ~ /G/){print $1"\t"$2}' | sort -rn
du -am --max-depth 1 | sort -rn | awk '($1 > 100){print $1"M\t"$2}'
du -am --max-depth 1 | sort -rn | awk '($1 > 100){print $1" "$2}' | sed ':a;s/\B[0-9]\{3\}\>/,&/;ta' | awk '{print $1"M\t"$2}'

fallocate

fallocate -l 200m 200m.size
fallocate -l 10g 10g.size

find

find . -maxdepth 1 -type f -size +100M -exec /bin/ls -lh {} + | sort -k2 | awk '{print $5"\t"$NF}'
find -type f -size +100M -exec ls -lh {} + | awk '{print $5"\t"$NF}' | sort -rn

sudo find /opt/app -name log4j-core-*.jar -exec zip -q -d {} org/apache/logging/log4j/core/lookup/JndiLookup.class \;
sudo find /opt/app -name log4j-core-*.jar | xargs -I {} sudo zip -q -d {} org/apache/logging/log4j/core/lookup/JndiLookup.class

firewalld

firewall-cmd --state
firewall-cmd --get-default-zone
firewall-cmd --get-zones

firewall-cmd --zone=internal --change-interface=eth0
firewall-cmd --zone=internal --remove-interface=eth0
firewall-cmd --zone=public --add-interface=eth0
firewall-cmd --get-active-zones

firewall-cmd --list-all
firewall-cmd --zone=public --list-all

firewall-cmd --zone=public --permanent --add-service=https
firewall-cmd --zone=public --permanent --add-port=1857/tcp
firewall-cmd --zone=public --permanent --add-port=2857-3857/tcp

firewall-cmd --permanent --add-rich-rule="rule family="ipv4" source address="10.8.5.7" port protocol="tcp" port="857" accept"

firewall-cmd --reload
systemctl reload firewalld

fpm

fpm -s python -t rpm --python-bin python2.7 --python-easyinstall easy_install-2.7 \
--python-install-lib /usr/lib/python2.7/site-packages pysftp

helm

helm install --set storage.aws.accessKey="AWS_ACCESS_KEY" --set storage.aws.secret="AWS_SECRET_KEY" --name k8s-app-cluster .
helm upgrade --set storage.aws.accessKey="AWS_ACCESS_KEY" --set storage.aws.secret="AWS_SECRET_KEY" k8s-app-cluster .

helm list
helm delete --purge k8s-app-cluster

iptables

cat > /etc/sysconfig/iptables <<EOF
*nat
:PREROUTING ACCEPT [0:0]
:INPUT ACCEPT [0:0]
:OUTPUT ACCEPT [0:0]
:POSTROUTING ACCEPT [0:0]
-A PREROUTING -d 5.6.7.8 -p tcp --dport 18080 -j DNAT --to 10.8.5.8:8080
-A POSTROUTING -d 10.8.5.0/24 -j SNAT --to 10.8.5.7
-A POSTROUTING -s 10.8.5.0/24 -o eth1 -j MASQUERADE
COMMIT
*filter
:INPUT ACCEPT [0:0]
:FORWARD ACCEPT [0:0]
:OUTPUT ACCEPT [0:0]
-A INPUT -m state --state RELATED,ESTABLISHED -j ACCEPT
-A INPUT -p icmp -j ACCEPT
-A INPUT -i lo -j ACCEPT
-A INPUT -p tcp -m state --state NEW -m tcp --dport 22 -j ACCEPT
-A INPUT -p tcp -m state --state NEW -m tcp --dport 2857:3857 -j ACCEPT
-A INPUT -p tcp -m state --state NEW -m udp --dport 53 -j ACCEPT
-A FORWARD -s 10.8.5.0/24 -j ACCEPT
-A FORWARD -m state --state RELATED,ESTABLISHED -j ACCEPT
-A INPUT -j REJECT --reject-with icmp-host-prohibited
-A FORWARD -j REJECT --reject-with icmp-host-prohibited
COMMIT
EOF

iptables-save

jq

cat config.json | jq
jq -r '.profiles[] | select(.name == "foobar") | .bazqux' config.json

jq -c '.[]' data.json > data.ndjson

kubectl

kubectl get pods --all-namespaces
kubectl get pods -n kube-system

watch -n 1 kubectl get pods

kubectl get pods -o wide
kubectl describe pods/k8s-app-pod-0
kubectl logs pods/k8s-app-pod-0

kubectl get svc/k8s-app-svc-0
kubectl get svc/k8s-app-svc-0 -o yaml
kubectl describe svc/k8s-app-svc-0

kubectl get pv
kubectl get pvc
kubectl get storageclass/gp2
kubectl get storageclass/gp2 -o yaml
kubectl describe storageclass/gp2

kubectl get sc
kubectl describe sc/gp2
kubectl patch sc gp2 -p '{"allowVolumeExpansion": true}'
kubectl edit pvc/k8s-app-svc-0

kubectl create secret tls k8s-app-ssl-cert --key sslcerts/star.heylinux.com.key --cert sslcerts/star.heylinux.com.crt

kubectl edit configmap aws-auth -n kube-system
kubectl edit svc/k8s-app-ingress

kubectl get configmap
kubectl edit cm/k8s-app-config

KUBECONFIG=k8s-env-1:k8s-env-2:k8s-env-3 kubectl config view --flatten > config
kubectl config current-context
kubectl config use-context k8s-env-1
kubectl config use-context k8s-env-2
kubectl config use-context k8s-env-3
kubectl --kubeconfig ~/.kube/k8s-env-1 get pods

kubectl exec -it k8s-app-pod-0 -- /bin/bash
kubectl exec -i k8s-app-pod-0 -- find /path/to/logdir/ -type d -name "2020*" -exec rm -r {} +

kubectl cp k8s-app-pod-0:/path/to/logdir k8s-app-pod-0_logdir

KUBECTL_EXTERNAL_DIFF=meld kubectl diff -f some-resources.yaml

kubectl run nginx --image=nginx --image-pull-policy=IfNotPresent --dry-run=client -o yaml > nginx-pod.yaml

# decrypt and export a secret
kubectl get secret tls-certs -o json \
| python -c 'import json,sys;obj=json.load(sys.stdin);print(obj["data"]["tls.crt"])' \
| base64 -d > tls.crt

# create ad-hoc-pod.yaml to view the configmap "heylinux-conf-d" key "foo.conf" as actual file format
apiVersion: v1
kind: Pod
metadata:
  name: ad-hoc-pod
spec:
  containers:
    - name: test-container
      image: busybox:latest
      command: [ "/bin/sh","-c","cat /etc/config/*" ]
      volumeMounts:
      - name: config-volume
        mountPath: /etc/config
  volumes:
    - name: config-volume
      configMap:
        name: heylinux-conf-d
        items:
        - key: foo.conf
          path: foo.conf
  restartPolicy: Never

# create pod ad-hoc-pod and export the configmap "heylinux-conf-d" key "foo.conf" as configmaps/foo.conf
kubectl apply -f ad-hoc-pod.yaml
kubectl logs ad-hoc-pod > configmaps/foo.conf

# create new configmap "heylinux-conf-d-backup" with configmaps/foo.conf
kubectl create configmap heylinux-conf-d-backup --from-file=configmaps/

# update the configmap "heylinux-conf-d" with configmaps/foo.conf
kubectl create configmap heylinux-conf-d --from-file=configmaps/ -o yaml --dry-run | kubectl apply -f -

lftp

lftp -d -e "set ssl:ca-file /etc/ssl/certs/vsftpd.pem" -u username,password 10.1.2.3
---
mput *.tgz
mkdir pkg_dir.20201225
mirror -R pkg_dir.20201225 pkg_dir.20201225

lftp -u username, -e "set sftp:connect-program 'ssh -p 22 -i /home/username/.ssh/id_rsa'" sftp://10.1.2.3

lvm

growpart /dev/nvme0n1 3
pvresize /dev/nvme0n1p3
pvscan
free_size=$(vgdisplay | grep Free | awk '{print $5}')
lvextend -L +${free_size} /dev/mapper/VolGroup00-root
xfs_growfs /dev/mapper/VolGroup00-root

pvcreate /dev/nvme1n1
pvresize /dev/nvme1n1
pvscan
vgextend /dev/VolGroup00 /dev/nvme1n1
free_size=$(vgdisplay | grep Free | awk '{print $5}')
lvextend -L +${free_size} /dev/mapper/VolGroup00-root
xfs_growfs /dev/mapper/VolGroup00-root

resize2fs /dev/mapper/VolGroup00-root

xfs_growfs -d /data
xfs_growfs /dev/nvme2n1

nc

# tcp
nc -kvl4p 8080
echo -e "hello this is damon" | nc -nv 10.1.2.3 8080
nc -nvz 10.1.2.3 8080

# udp
nc -uvl4p 8053
echo -e "hello this is damon" | nc -nvu 10.1.2.3 8053
nc -nvuz 10.1.2.3 8053

# port forwarding
nc -lk 7017 | nc localhost 27017
socat TCP-LISTEN:7017,reuseaddr,fork TCP:localhost:27017

pip

pip install --no-cache-dir -i https://mirrors.aliyun.com/pypi/simple -r requirements.txt

postgresql

psql -h 127.0.0.1 -U postgres
---
\l
\c dbname
\d
SELECT id,email,name FROM people ORDER BY id;
DELETE FROM people WHERE id=857;
\du
\dt public.*
CREATE USER dbro WITH ENCRYPTED PASSWORD 'dbpass';
GRANT USAGE ON SCHEMA public TO dbro;
GRANT SELECT ON ALL TABLES IN SCHEMA public TO dbro;
\q

python

echo '{"json":"obj"}' | python -m json.tool

echo '{"foo": "lorem", "bar": "ipsum"}' | python -c 'import json,sys;obj=json.load(sys.stdin);print(obj["foo"])'
python -c 'import yaml,sys;obj=yaml.safe_load(sys.stdin);print(list(obj["foo"])[-1])' < /path/to/file.yml
whoami | python -c 'import sys;username=sys.stdin.read().splitlines()[0];print(username)'

python2 -m SimpleHTTPServer 8080
python3 -m http.server 8080
python3 -m http.server 8080 --bind $(ipconfig getifaddr en0)

python - <<EOF
import sys
for i in range(3): print(i)
EOF

python -c "import os
env_lang = os.getenv('LANG')
if ('UTF-8' in env_lang):
    print('INFO: UTF-8 is supported by {0}'.format(env_lang))
else:
    print('WARN: UTF-8 is not supported')"

# remove non utf8 characters
str.encode("ascii", "ignore").decode()

# run Python command with unbuffered output and log to both terminal and file
python3 -u script.py | tee -a out.txt

route

route -n

route add default gw 10.8.1.1
route add -net 10.8.5.0 netmask 255.255.255.0 gw 10.8.5.1 dev eth1 metric 101

rpm

rpm -qa | grep unzip
rpm -ql unzip
rpm -qi unzip
rpm -qif /usr/bin/unzip
rpm -Uvh unzip-6.0-21.el7.x86_64.rpm

rsync

rsync -a --exclude "plugins/linux_amd64" repo/terraform-iac/ backups/terraform-iac.$(date +%Y%m%d)

rsync -e "ssh -p 22" --timeout=10 --delete --log-file=logs/rsync.$(date +%Y%m%d).log \
-ravz backups user@hostname:/opt/backups

screen

screen -dmS s3_sync_20251208  # create session, detached, specify session name
screen -ls  # list sessions

screen -r s3_sync_20251208  # attach session

screen -x s3_sync_20251208  # join attached session

ctrl-a d  # detach session

exit  # close current session, ctrl-d
screen -S s3_sync_20251208 -X quit  # kill session

sed

sed -i --follow-symlinks '/max_log_file/ s/8/100/' /etc/audit/auditd.conf
sed -i --follow-symlinks '/^max_log_file_action/ s/=.*/= ROTATE/' /etc/audit/auditd.conf

sed -i --follow-symlinks '/GRUB_CMDLINE_LINUX/ s/\"$/ ipv6.disable=1 audit=1\"/' /etc/sysconfig/grub
sed -i --follow-symlinks '/^AllowUsers/ s/$/ ec2-user/' /etc/ssh/sshd_config

sed -i.bak '/port=0/d' kube-scheduler.yaml
sed -i "/^data:/a \  ssl_crt: ${ssl_crt_base64}" anaconda-enterprise-certs.yml

sed -i '/ swap / s/^\(.*\)$/#\1/g' /etc/fstab

sed -i '/kexalgorithms/d' /etc/ssh/sshd_config

sed -e 's|^mirrorlist=|#mirrorlist=|g' \
    -e 's|^#baseurl=http://mirror.centos.org|baseurl=https://vault.centos.org|g' \
    -i.bak \
    /etc/yum.repos.d/CentOS-*.repo

setfacl

mkdir pkg_dir
chown root:root pkg_dir
chmod 770 pkg_dir

setfacl -dm u:tom:rwx -dm g:ops:rwx pkg_dir
setfacl -m u:tom:rwx -m g:ops:rwx pkg_dir

mkdir pkg_dir/sub_dir
touch pkg_dir/sub_dir/file.txt

getfacl -R pkg_dir

setfacl -b pkg_dir

ssh

# ssh tunneling and port forwarding
# request -> local 10.8.5.7:18080 -> remote_host 5.6.7.8:22 -> dest 10.1.2.8:8080
ssh -i ${sshkey} -p ${sshport} -f -NTL ${local_ip}:${local_port}:${dest_ip}:${dest_port} ${sshuser}@${remote_host}
ssh -i /path/to/sshkey -p 22 -f -NTL 10.8.5.7:18080:10.1.2.8:8080 sshuser@5.6.7.8

# request -> remote_host_lan 10.1.2.7:8080 -> remote_host 5.6.7.8:22 -> local 10.8.5.7:18080
# enable GatewayPorts option in sshd_config
ssh -i ${sshkey} -p ${sshport} -f -NTR ${remote_lan_ip}:${remote_port}:${local_ip}:${local_port} ${sshuser}@${remote_host}
ssh -i /path/to/sshkey -p 22 -f -NTR 10.1.2.7:8080:10.8.5.7:18080 sshuser@5.6.7.8

# ssh jumpserver
## jump over proxy to dest_host 10.8.5.7:22
## support multiple proxies: user1@proxy1:port1,user2@proxy2:port2
ssh -i /path/to/sshkey -p 22 -J jumpuser@proxy.example.org:10022 user@10.8.5.7

## /etc/ssh/sshd_config on proxy.example.org
Match User jumpuser
  PermitTTY no
  X11Forwarding no
  PermitTunnel no
  GatewayPorts no
  ForceCommand /usr/sbin/nologin

## ~/.ssh/config on client
Host 10.8.5.*
    ProxyJump jumpuser@proxy.example.org:10022

# sshkey
ssh-keygen -t rsa -b 4096 -C "mcsrainbow@heylinux.com" -f mcsrainbow_id_rsa
ssh-copy-id -i /path/to/ssh-pub-key ssh-user@10.8.5.8

# sshfs
sshfs -o allow_other,port=22,IdentityFile=/path/to/ssh-key user@10.8.5.8:/path/to/dir /path/to/mnt/dir

systemd

cat > /etc/systemd/system/nifi.service <<EOF
[Unit]
Description=NiFi Service
After=syslog.target

[Service]
Type=forking
ExecStart=/opt/nifi/bin/nifi.sh start
ExecStop=/opt/nifi/bin/nifi.sh stop
User=ec2-user
LimitNOFILE=65536
LimitNPROC=4096
LimitFSIZE=infinity

[Install]
WantedBy=multi-user.target
EOF

systemctl daemon-reload
systemctl enable nifi.service

systemctl start nifi
systemctl stop nifi
systemctl status nifi

tar

tar --exclude=pkg_dir/pkg_dir_file1.txt --exclude=pkg_dir/sub_dir1 -cvzpfh pkg_dir.$(date +%Y%m%d).tgz pkg_dir

tar tzvpf pkg_dir.20201225.tgz

mkdir pkg_dir.20201225
tar xzpf pkg_dir.20201225.tgz -C pkg_dir.20201225

tcpdump

tcpdump -i any port 8080
tcpdump -i any tcp port 8080 -w tcp_8080.cap
tcpdump -r tcp_8080.cap

tcpdump -i any icmp

tcpdump -i any -an 'src portrange 10021-11021 or src port 21'

tcpdump -i any host 10.1.2.2
tcpdump -i any src host 10.1.2.2

tcpdump -i any src net 10.1.0.0/24
tcpdump -i any dst net 10.1.0.0/24

tcpdump -i any -nvX src 10.1.2.2 and dst port 22
tcpdump -i any -nvX src net 192.168.0.0/16 and dst net 10.0.0.0/8 or 172.16.0.0/16

tcpdump -i any -w traffic.pcap host 8.5.7.3 and port 8080
tcpdump -i any -n -X host 8.5.7.3 and port 8080

tmux

# 按键方式不是组合键, 是前缀键
# 1. 按住ctrl不放开
# 2. 按b
# 3. 全部放开
# 4. 快速按d

tmux new -ds s3_sync_20251208  # detached, specify session name
tmux ls  # list-sessions

tmux neww -t s3_sync_20251208 -n logs  # new-window
tmux neww -t s3_sync_20251208 -n temp  # new-window

tmux lsw -t s3_sync_20251208  # list-windows

tmux a -t s3_sync_20251208  # attach-session
tmux renamew main  # rename-window

tmux selectw -t logs  # select-window, ctrl-b 1
tmux selectw -t temp  # select-window, ctrl-b 2

tmux splitw -h  # split-window
tmux splitw -v  # split-window

ctrl-b arrow_keys  # switch pane

exit  # close current pane, ctrl-d

tmux detach  # ctrl-b d
tmux a -t s3_sync_20251208:main  # attach-session

tmux kill-session -t s3_sync_20251208  # kill-session

uv

# initialize project
pip install uv
uv init myapp --python 3.12
cd myapp
uv venv

cat <<'EOT' >> pyproject.toml

[tool.uv]
managed = true

[[tool.uv.index]]
name = "aliyun"
url = "https://mirrors.aliyun.com/pypi/simple/"
default = true
EOT

uv add fastapi uvicorn

export PYTHONPATH=src
uv run python main.py

uv pip freeze > requirements.txt
uv lock

# load project
uv sync --locked

vim

# 光标移动
- `0`  移动到行首
- `$`  移动到行尾
- `^`  移动到第一个非空白字符

- `w`  移动到下一个单词开头
- `b`  移动到单词开头

- `gg` 跳到文件开头
- `G`  跳到文件末尾
- `%`  跳转到匹配括号
- `[:n/ngg/nG]` 跳到第`n`行

# 插入模式
- `i`   在光标前插入
- `a`   在光标后插入
- `esc` 退出插入模式

# 编辑操作
- `x`   删除光标处字符
- `dd`  删除当前行
- `ndd` 删除`n`行
- `dw`  删除当前单词
- `ndw` 删除`n`个单词
- `D`   删除到行尾(同`d$`)
- `d0`  删除到行首
- `dG`  删除到文件末尾
- `dgg` 删除到文件开头

- `u`         撤销
- `U`         撤销整行
- `ctrl + r`  恢复撤销

- `yy`  复制当前行
- `nyy` 复制`n`行
- `Y`   复制到行尾(同`y$`)
- `y^`  复制到行首
- `p`   在光标后粘贴
- `P`   在光标前粘贴

# 搜索与替换
- `/pattern` 向下搜索`pattern`
- `?pattern` 向上搜索`pattern`
- `n`        跳转到下一个匹配
- `N`        跳转到上一个匹配
- `*`        正向搜索光标所在单词
- `#`        反向搜索光标所在单词
- `:%s/foo/bar/g`  全文替换`foo`为`bar`
- `:%s/foo/bar/gc` 全文替换 并逐个确认
- `:s/foo/bar/g`   行内替换`foo`为`bar`
- `:s/foo/bar/gc`  行内替换 并逐个确认

# 可视模式
- `v`         字符选择模式
- `V`         行选择模式
- `ctrl + v`  块选择模式(列选择)
- `esc + esc` 退出可视模式

- `y` 复制选中文本
- `d` 删除选中文本
- `u` 将选中的文本转换为小写
- `U` 将选中的文本转换为大写
- `>` 缩进选中文本
- `<` 反缩进选中文本
- `=` 自动对齐格式化选中文本

# 文件操作
- `:w`         保存
- `:w!`        强制保存
- `:w foo.txt` 另存为`foo.txt`
- `:wq`        保存并退出(同`:x` `ZZ`)
- `:wq!`       强制保存并退出
- `:q`         退出
- `:q!`        强制退出(放弃修改,同`ZQ`)

# 常用命令
- `:syntax off` 关闭语法高亮
- `:noh`        清除搜索高亮
- `:set number` 显示行号
- `:set paste`  开启粘贴模式
- `:set wrap`   开启换行

wget

wget -r --no-parent https://repo.anaconda.com/pkgs/r/linux-64/

wget -m -np -nH --cut-dirs=2 -R --regex-type pcre --accept-regex '(.*s3fs.*)' https://repo.anaconda.com/pkgs/main/linux-64/

wget --header "PRIVATE-TOKEN: <your_access_token>" \
"https://jihulab.com/api/v4/projects/857857/repository/files/folder%2Fpackage.tar/raw?ref=main" \
-O package.tar

yq

kustomize build overlays/development | yq eval --prettyPrint --indent=2
yq 'select(.kind == "Ingress" and .metadata.name == "foobar-ingress") | .spec.rules[].http.paths[].path' bu-project-foobar.yaml

yum

mkdir /tmp/nginx_rpms
yum install --enablerepo epel --downloadonly --downloaddir=/tmp/nginx_rpms nginx nginx-mod-stream

cd /tmp/nginx_rpms
yum localinstall *.rpm --disablerepo='*'

zip

zip --symlinks -r9 pkg_dir.$(date +%Y%m%d).zip pkg_dir -x "pkg_dir/pkg_dir_file1.txt" "pkg_dir/sub_dir1/*"

unzip -l pkg_dir.20201225.zip

zip -r9 pkg_dir.20201225.zip pkg_dir/sub_dir1

mkdir pkg_dir.20201225
unzip pkg_dir.20201225.zip -d pkg_dir.20201225

# zip all files including hidden, excluding .DS_Store and archive itself
cd /path/to/directory
zip -r archive.zip . -x ".DS_Store" "archive.zip"

misc

# change password in one command line
echo "password" | passwd --stdin username

# create a default home directory and update user groups
mkhomedir_helper username
chmod 700 /home/username
usermod -s /bin/bash username
usermod -a -G adm,sudo,docker username

# rename filename suffix svg.png as png
\ls *.svg.png | xargs basename -s .svg.png | xargs -I {} mv {}.svg.png {}.png

# update file in one command line
cat <<EOF | sudo tee -a /etc/modules-load.d/k8s.conf
br_netfilter
EOF

# processes order by mem/cpu desc
ps -eo pid,ppid,pmem,pcpu,cmd --sort=-pmem
ps -eo pid,ppid,pmem,pcpu,cmd --sort=-pcpu

# disable history of current shell
set +o history

# keep alive
sleep infinity

# list in natural order
ls -lvh

# delete a single command with id number from shell history
history -d 857

# watch usage metrics of cpu, memory, disk io, network
vmstat -n 1
iostat -dxm 1
sar -n DEV 1
htop
iotop
iftop

# bandwidth testing
iperf3

# generate a list of checksums for any file that matches *.csv
md5sum *.csv > checklist.chk
# run through the list to check them
md5sum -c checklist.chk

# create a symlink
ln -sfT app-1.1 app

# expansion of variables inside single quotes
# cat echo.sh
# echo $1
dst_url="/path/to/dst_url"
./echo.sh '/path/to/src_url/(.*) -> '"$dst_url"'/$1'
# /path/to/src_url/(.*) -> /path/to/dst_url/$1

# error handling in bash scripts
set -e            # when a command fails, set -e ensures that the entire script exits instead of continuing to the next line
set -u            # treat unset variables as errors and exit immediately
set -f            # disable filename expansion (globbing) when encountering characters like *, ?, etc.
set -o pipefail   # cause a pipeline (e.g., command1| command 2 | grep foo) to fail if any command within the pipeline errors
set -euo pipefail # both -e, -u and -o pipefail

# rename files by removing the .j2 suffix
for i in $(find . -type f -name "*.j2"); do mv "$i" "${i%.j2}";done