🐞 Bash Bug: Extra Space in Parameter Expansion

In July 2025, I discovered a subtle bug in Bash related to parameter expansion when combining a variable with a quoted string and a trailing $.

💡 The Bug

export S=" "
echo $S"hello"$

🔴 Actual Output:

 hello$

✅ Expected Output:

hello$

This unexpected space suggests a bug in how Bash parses or expands variables when combined with quoted strings and special symbols.

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🧾 Report

I reported this bug to the GNU Bash maintainers through Savannah. The official bug ID is:

• 🔗 Bug #67358 on Savannah

The issue was confirmed and fixed in the development branch by Chet Ramey, the Bash maintainer.

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🔐 Verified Developer Response (PGP Signed)

Chet Ramey responded with two digitally signed messages confirming the bug and its fix.

You can find the original signature files here:

• chet-response-1.asc
• chet-response-2.asc

You can verify the signatures using GPG:

gpg --verify chet-response-1.asc
gpg --verify chet-response-2.asc

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📂 Files

• test_case.sh – Minimal test case showing the bug
• report.txt – Full bug report as submitted
• links.md – References to Bash and bug tracker