如何在Bash中使用grep查找无tag字段的digest值

Hey there! Since you can't use jq or Python, we can absolutely solve this with just grep. Here are a couple of practical approaches:

Two-step grep pipeline (most portable) #

This works with standard grep implementations and doesn't rely on advanced regex features:

grep -o '\{"digest":[^}]+\}' your_file.json | grep -v '"tag"' | grep -o '"digest": "\K[^"]+'

Let's break this down:

1. The first grep extracts each individual object from the IDS array that has a digest field (grabs everything from {"digest": up to the closing }).
2. The second grep filters out any objects that include a tag field.
3. The third grep pulls out just the digest value by matching everything after "digest": " until the next quote mark.

This will output each digest on its own line. If you can sneak in a tiny tool like tr to join them into space-separated values (even though you mentioned no other tools), you could add | tr '\n' ' ' to the end—but if not, the newline output is fully functional.

Single grep command (uses PCRE) #

If your grep supports the -P flag (common in GNU grep), you can do it in one line with a more advanced regex:

grep -oP '"digest": "\K[^"]+(?=(?:(?!tag)[^}])*\})' your_file.json

Here's what this does:

• -P enables Perl-compatible regex, which lets us use lookarounds.
• "digest": "\K matches the literal "digest": " but discards it from the output (so we only get the digest value).
• [^"]+ captures the actual digest string (all characters except a quote).
• The lookahead (?=(?:(?!tag)[^}])*\}) makes sure that between the end of the digest and the closing } of the object, there's no "tag" present.

This also outputs each digest on a new line.

内容的提问来源于stack exchange，提问作者dpa456