Bash tool uses login shell (-l) causing unwanted output
Status Closed — not planned
Maintainer reply ✓ Yes — wolffiex
Workaround ✓ Mentioned in thread ↓
Activity 12 comments · opened Nov 18, 2025 · closed Jan 27, 2026
💡 Likely answer: A maintainer (wolffiex, collaborator)
responded on this thread — see the highlighted reply below.
Issue
Every bash command is executed as a login shell, sourcing ~/.bash_profile / ~/.profile on each invocation. This pollutes command output with login script messages and adds unnecessary overhead.
Steps to Reproduce
- Add any output statement to
~/.bash_profile(e.g.,echo "Login shell initialized") - Execute any Bash tool command through Claude Code
- Observe the extra output from the login script
Verification
$ shopt login_shell
login_shell onExpected
Commands should run in non-login shells. The -l flag should not be used unless specifically needed.
Impact
- Extraneous output in command results
- Performance overhead from repeatedly sourcing login scripts
- Unexpected environment modifications
12 Comments
Found 2 possible duplicate issues:
This issue will be automatically closed as a duplicate in 3 days.
🤖 Generated with Claude Code
The other issues are not duplicates. #11684 proposes several solutions, only one of which solves this problem.
I have this problem due to .bash_profile including a CD command to a common workspace directory which screws up claude's Bash tool since the working directory gets modified -_-
+1 on making shell invocation configurable. I'd additionally want to be able to set the shell used. I'm using zsh but want claude to run bash. Setting
"SHELL": "/bin/bash"under"env"insettings.jsonappears to be ignored.I added a (secret) env var for this:
CLAUDE_BASH_NO_LOGINCan you try setting this and confirm it's what you want? If it is I will document it at a minimum and consider making it the default
Works for me, thanks.
Unless you can find any reason why the -l flag was added in the first place, I concur with removing it by default.
Tested
CLAUDE_BASH_NO_LOGIN- Works Great!@wolffiex Thank you for implementing this fix! I've tested it thoroughly and it works perfectly.
Test Environment:
Test Results:
After setting
CLAUDE_BASH_NO_LOGIN=1in~/.claude/settings.local.json:✅ Edit Tool: Multiple consecutive Read → Edit operations succeeded
✅ No Errors: "File has been unexpectedly modified" completely resolved
✅ Stable: Works consistently across different file types
Real-World Impact:
This fix also resolves the Edit tool timestamp issue I reported in #11684, confirming that both issues share the same root cause:
bash -lsourcing profile scripts.Feedback:
The fix works excellently! Suggestions for next steps:
Thanks again for the quick turnaround on this!
Thank you for at least the workaround, this solves an issue I have because I include
cd ~in my login profile to make my tmux workflow easier.I'd like to see this become the default -- tools should not be starting "login" shells because login profiles commonly include extra setup that's not necessary or appropriate for every subshell invocation.
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This is a lot late, but this is now the default behavior in Claude Code. Thanks for the feedback!