Shell脚本中使用sed提取JSON首个id值失败求助

我来帮你搞定这个问题！你的sed命令没输出，主要是因为正则表达式没匹配到目标行，咱们一步步来分析和解决：

问题根源分析 #

先看你写的sed表达式：

sed -n -e 's/"id":\\ \\([0-9]\\+\\),/\\1/p'

这里有几个关键问题：

• 你用\\ \\试图匹配空格，但实际JSON里"id"后面只有一个空格，多余的转义反而让匹配逻辑混乱；
• 目标行的"id": 1234332后面没有逗号，但你的表达式强制要求匹配逗号，直接导致完全匹配失败；
• 没有考虑JSON行首的缩进空格，进一步降低了匹配概率。

修复后的sed命令 #

把提取id的行替换成下面的命令，就能正确捕获到顶层的id值：

id=$(echo "$release" | sed -n 's/^ *"id": *\([0-9]\+\),*$/\1/p' | head -n 1)

我来拆解一下这个正则的逻辑：

• ^ *：匹配行首任意数量的空格，适配JSON的缩进格式；
• "id": *：匹配"id":以及后面任意数量的空格（兼容不同的格式化风格）；
• \([0-9]\+\)：捕获连续的数字序列，也就是我们需要的id值；
• ,*$：匹配行尾可选的逗号，兼容JSON中某些字段后面带逗号的情况；
• \1：输出捕获到的数字内容。

更稳妥的替代方案：用jq处理JSON #

其实用sed处理结构化的JSON是很脆弱的——如果JSON的格式稍有变化（比如空格调整、换行位置改变），sed命令就可能失效。更专业的做法是用专门的JSON处理工具jq，一行就能精准提取顶层id：

# 直接整合curl和jq，无需额外的echo和sed
id=$(curl -H "Authorization:token xxxxxxxxxxxxxxxxxxxxxx" -H "Content-Type: application/json" https://api.github.com/repos/octocat/Hello-World/releases/tags/v1.0.0 | jq -r '.id')

• -r参数：让jq输出原始字符串（不带引号）；
• .id：直接访问JSON顶层的id字段，完全不会误抓嵌套在author或assets里的其他id值。

你的原脚本与返回JSON #

原Shell脚本 #

#!/bin/bash
release=$(curl -H "Authorization:token xxxxxxxxxxxxxxxxxxxxxx" -H "Content-Type: application/json" https://api.github.com/repos/octocat/Hello-World/releases/tags/v1.0.0)
id=$(echo "$release" |sed -n -e 's/"id":\\ \\([0-9]\\+\\),/\\1/p' | head -n 1 | sed 's/[[:blank:]]//g')
echo $id

curl返回的JSON #

{
 "url": "https://api.github.com/repos/octocat/Hello-World/releases/1",
 "html_url": "https://github.com/octocat/Hello-World/releases/v1.0.0",
 "assets_url": "https://api.github.com/repos/octocat/Hello- World/releases/1/assets",
 "upload_url": "https://uploads.github.com/repos/octocat/Hello- World/releases/1/assets{?name,label}",
 "tarball_url": "https://api.github.com/repos/octocat/Hello- World/tarball/v1.0.0",
 "zipball_url": "https://api.github.com/repos/octocat/Hello- World/zipball/v1.0.0",
 "id": 1234332,
 "node_id": "MDc6UmVsZWFzZTE=",
 "tag_name": "v1.0.0",
 "target_commitish": "master",
 "name": "v1.0.0",
 "body": "Description of the release",
 "draft": false,
 "prerelease": false,
 "created_at": "2013-02-27T19:35:32Z",
 "published_at": "2013-02-27T19:35:32Z",
 "author": {
 "login": "octocat",
 "id": 1353322,
 "node_id": "MDQ6VXNlcjE=",
 "avatar_url": "https://github.com/images/error/octocat_happy.gif",
 "gravatar_id": "",
 "url": "https://api.github.com/users/octocat",
 "html_url": "https://github.com/octocat",
 "followers_url": "https://api.github.com/users/octocat/followers",
 "following_url": "https://api.github.com/users/octocat/following{/other_user}",
 "gists_url": "https://api.github.com/users/octocat/gists{/gist_id}",
 "starred_url": "https://api.github.com/users/octocat/starred{/owner} {/repo}",
 "subscriptions_url": "https://api.github.com/users/octocat/subscriptions",
 "organizations_url": "https://api.github.com/users/octocat/orgs",
 "repos_url": "https://api.github.com/users/octocat/repos",
 "events_url": "https://api.github.com/users/octocat/events{/privacy}",
 "received_events_url": "https://api.github.com/users/octocat/received_events",
 "type": "User",
 "site_admin": false
 },
 "assets": [
 {
 "url": "https://api.github.com/repos/octocat/Hello- World/releases/assets/1",
 "browser_download_url": "https://github.com/octocat/Hello- World/releases/download/v1.0.0/example.zip",
 "id": 56432211,
 "node_id": "MDEyOlJlbGVhc2VBc3NldDE=",
 "name": "example.zip",
 "label": "short description",
 "state": "uploaded",
 "content_type": "application/zip",
 "size": 1024,
 "download_count": 42,
 "created_at": "2013-02-27T19:35:32Z",
 "updated_at": "2013-02-27T19:35:32Z",
 "uploader": {
 "login": "octocat",
 "id": 5663322,
 "node_id": "MDQ6VXNlcjE=",
 "avatar_url": "https://github.com/images/error/octocat_happy.gif",
 "gravatar_id": "",
 "url": "https://api.github.com/users/octocat",
 "html_url": "https://github.com/octocat",
 "followers_url": "https://api.github.com/users/octocat/followers",
 "following_url": "https://api.github.com/users/octocat/following{/other_user}",
 "gists_url": "https://api.github.com/users/octocat/gists{/gist_id}",
 "starred_url": "https://api.github.com/users/octocat/starred{/owner} {/repo}",
 "subscriptions_url": "https://api.github.com/users/octocat/subscriptions",
 "organizations_url": "https://api.github.com/users/octocat/orgs",
 "repos_url": "https://api.github.com/users/octocat/repos",
 "events_url": "https://api.github.com/users/octocat/events{/privacy}",
 "received_events_url": "https://api.github.com/users/octocat/received_events",
 "type": "User",
 "site_admin": false
 }
 }
 ]
}

内容的提问来源于stack exchange，提问作者Sumith08