Recently in Shell Category

BASH regular expression

Vote 0 Votes

e.g. Get first 7.x dir name

[[ `curl -s` =~ $RE ]]
echo ${BASH_REMATCH[1]}



Vote 0 Votes

dehydrated 之前叫做 因為名稱違反 Let's Encrypt 的商標而改名

以下範例 Document Root 在 /var/www/html, dehydrated 放在 /usr/local
cd /usr/local
git clone
cd dehydrated
echo "" > domains.txt
mkdir -p /var/www/html/.well-known/acme-challenge # 另一個方法是設 alias (官網教的方法)
echo BASEDIR=/usr/local/dehydrated > config
echo WELLKNOWN=/var/www/html/.well-known/acme-challenge >> config
./dehydrated --register --accept-terms
./dehydrated -c

Let's Eencrypt 憑證有效期只有三個月, 到期前要再來執行 dehydrated -c
可排程每月執行, 剩餘時間要少於 30 天才會 renew, 不然只會提示 Longer than 30 days. Skipping

若機器有防火牆, 需開放以下 IP (for ACME challenge)

Apache 設定
Unmark Include conf/extra/httpd-ssl.conf in httpd.conf
conf/extra/httpd-ssl.conf 內容
SSLCertificateFile /usr/local/dehydrated/certs/
SSLCertificateKeyFile /usr/local/dehydrated/certs/
SSLCertificateChainFile /usr/local/dehydrated/certs/
SSLCACertificateFile /usr/local/dehydrated/certs/

PowerShell OpenSSH

Vote 0 Votes

PowerShell OpenSSH 是微軟 PowerShell Team 所 build 的 OpenSSH,
其針對 Windows 環境有些調整, 例如 ssh-keygen 會產在 Key 在 %USERPROFILE\.ssh
比起其他的版本, 更適合在 Windows 使用, 目前仍是 Pre-release

ref. Windows PowerShell Blog - OpenSSH for Windows Update

XML formating

Vote 0 Votes

| xmllint --format - # need libxml2 package
| xmlstarlet fo # need xmlstarlet
Make it more readable.

JSON formating

Vote 0 Votes

| python -m json.tool # need python package
| jq . # need jq package
Make it more readable.

Server Side sshd_config
ClientAliveInterval 60
ClientAliveCountMax 3


Client Side ssh_config
ServerAliveInterval 60

ssh user@host bash -s -- <

You can add arguments if you need.
ssh user@host bash -s -- < argv1


Vote 0 Votes

一般是建 Key 來達成 ssh 免密碼, 若不想建 Key, 可以用 sshpass
sshpass 可以在 ssh 時自動將密碼帶入
密碼可以用檔案(-f filename)或參數(-p password)或變數SSHPASS(-e)帶入
sshpass -f pass_file ssh
sshpass -p password ssh
export SSHPASS=password
sshpass -e
當然也可以直接執行所連線主機的 command
sshpass -e cat /etc/hosts

dcmd dssh

Vote 0 Votes

dcmd 可以將 command 一次下到多台機器,
前提是要先建立 ssh key, 管理端那台必需先把 public key 送到各台的 authorized_keys
機器清單存在 /etc/dcmd.hosts
然後就可以用 dssh 批次下指令, 例如 dssh uptime
# dssh uptime
host1 14:05:44 up 18 days, 4:12, 0 users, load average: 0.11, 0.10, 0.09
host2 14:05:45 up 19 days, 4:53, 39 users, load average: 1.37, 1.08, 1.08
host3 14:05:45 up 50 days, 4:28, 5 users, load average: 6.06, 6.02, 6.01

Shell Color Output

Vote 0 Votes

tput sgr0 # default terminal
tput setab [1-7] # Set the background color
tput setaf [1-7] # Set the foreground color

color is
0 black
1 red
2 green
3 yellow
4 blue
5 magenta
6 cyan
7 white

e.g. color output in red
# echo "`tput setaf 1`Red Color`tput sgr0`"
Red Color

ref. How to change the output color of echo in Linux

About this Archive

This page is an archive of recent entries in the Shell category.

Security is the previous category.

Software is the next category.

Find recent content on the main index or look in the archives to find all content.

Monthly Archives