當個好編劇，產出好腳本 - Shell Script (下) - iT 邦幫忙::一起幫忙解決難題，拯救 IT 人的一天

2022 iThome 鐵人賽

DAY 29

自我挑戰組

寫程式帶給我的無形快樂系列第 29 篇

當個好編劇，產出好腳本 - Shell Script (下)

14th鐵人賽

shan33

2022-10-14 00:07:32

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這篇主要會觀摩 vue-good-table-next 的 release shell script 內容

主要用到這五個指令

set
grep
read
sed
if ... fi

set

用法:

set -options arguments

# use to exit when the command exits with a non-zero status
# 指令回傳值若不等於 0，則立即退出 shell
# 當錯誤發生，用來中斷程式
set -e

grep

用來搜尋匹配 pattern 的字串，支援 Regular Expression

用法:

grep [options] pattern [files]
# 例如 grep "string" file name

假使有一個 test.txt 檔案內容

Welcome to Linux !
Linux is a free and opensource Operating system that is mostly used by
developers and in production servers for hosting crucial components such as web
and database servers. Linux has also made a name for itself in PCs.
Beginners looking to experiment with Linux can get started with friendlier linux
distributions such as Ubuntu, Mint, Fedora and Elementary OS.

執行

grep "Linux" test.txt # 搜尋檔案中 Linux 字串

grep demo
會印出整行文字，並把搜尋的關鍵字 highlight ！

如果關鍵字沒有出現顏色，可以加上 --color

grep --color "Linux" test.txt # 搜尋

如果要搜尋整個目錄下的檔案 (包含子目錄)，可以使用 -r (recursively)

grep -r "linux" *

忽略搜尋關鍵字的大小寫，使用 -i

grep -i "linux" welcome.txt

以上 grep 範例摘自 Grep Command in Linux/UNIX

read

從輸入中讀取一行，把輸入行的每個欄位的值指定給 shell 變數

# read 用來讀取螢幕輸入或是讀取檔案內容
read -p  "please input you  name: " firstname #獲取輸入變數，存入 firstname
read -p  "please input you age: " age         #獲取輸入變數，存入 age
echo "you name is $firstname ,age is $age"    #輸出變數內容

常用 option

-p (prompt): 輸入文字前，會印出的訊息內容
-s (secret/silent): 隱藏使用者輸入的文字，例如輸入密碼時
-n (number): 限制輸入文字的長度
-t (timeout): 限制使用者輸入文字的時間

read –p "Please type your username" username
read –s –p "Please type your password" $password
read –n 8 –p “Please type your username not exceeding 8 characters” username

echo "What is the capital of Japan? Answer in 5 seconds"
read -t 5 answer # 等待使用者 5 秒內輸入

if [ "$answer" = "tokyo" ] || [ "$answer" = "Tokyo" ];
then
echo "Your answer is Correct!"
else
echo "Your answer is Wrong!"
fi

以上 read 範例摘自How to Use the read Command in Bash

sed

Stream editor 處理文字，也支援 Regular Expression
sed 一次處理一行，主要用來搜尋、取代、刪除檔案中的文字

取代用法:

# 會取代每一行第一個出現的 old_string
sed 's/old_string/new_string/' filename.txt

# 取代每一行所有的 old_string
sed 's/old_string/new_string/g' filename.txt

刪除用法:

# 刪除指定行數
# 用法: sed '[first line to delete] [last line to delete] d' test.txt
sed '2,4 d' test.txt # 刪除 test.txt 檔案中第2行到第4行

# 匹配 Regex 規則的刪除
# 用法: sed '/regex/ d' test.txt
sed '/^#/ d' test.txt # 刪除#開頭的每一行

if...fi

用法:

if [ expression ] 
then 
   Statement(s) to be executed if expression is true 
fi

#!/bin/sh

a=10
b=20

if [ $a == $b ]
then
   echo "a is equal to b"
fi

if [ $a != $b ]
then
   echo "a is not equal to b"
fi

結果會印出

a is not equal to b

以上 if...fi 範例摘自Unix / Linux Shell - The if...fi statement

白話拆解

拆解 release.sh 的內容

set -e

# 搜尋 package.json 檔案中有 "version" 出現的那一行
# 使用 Regular Expression 擷取出目前版本號
echo "Current version:" $(grep version package.json | sed -E 's/^.*"([0-9][^"]+)".*$/\1/')
echo "Enter version e.g., 4.0.1: "

# 讀取使用者輸入的版本號
read VERSION 

# 再次詢問新版本號是否正確 (-n 1 限制一個字元)
read -p "Releasing v$VERSION - are you sure? (y/n)" -n 1 -r
echo    # (optional) move to a new line
if [[ $REPLY =~ ^[Yy]$ ]]
then
  echo "Releasing v$VERSION ..."

  # clear existing ts cache
  rm -rf node_modules/.rts2_cache

  # generate the version so that the changelog can be generated too
  yarn version --no-git-tag-version --no-commit-hooks --new-version $VERSION

  yarn run build
  yarn run build:dts
  yarn run test:dts

  # 自動產生 changelog
  yarn run changelog
  yarn prettier --write CHANGELOG.md
  echo "Please check the git history and the changelog and press enter"
  read OKAY

  # commit and tag (加入異動的兩隻檔案 CHANGELOG.md 和 package.json)
  git add CHANGELOG.md package.json
  git commit -m "release: v$VERSION"
  git tag "v$VERSION"

  # commit 
  yarn publish --tag next --new-version "$VERSION" --no-commit-hooks --no-git-tag-version

  # publish (push version 標籤 以及 檔案變更)
  git push origin refs/tags/v$VERSION
  git push
fi