{"version":"2.1.317","anchor":"background-shell-tail-pipe-notes","canonical_anchor":"background-shell-tail-pipe-notes","heading":"Bash keeps the full output when a command pipes into tail","tier":"notice","area":"Bash","scope":"individual","heads_up":false,"url":"https:\/\/changelogs.core-directive.com\/v\/2.1.317\/e\/background-shell-tail-pipe-notes","release_url":"https:\/\/changelogs.core-directive.com\/v\/2.1.317","markdown":"### Bash keeps the full output when a command pipes into tail\n\nWhen a command pipes into `tail`, Bash keeps a saved copy of the full output and tells Claude where it is; background shells can also add an end note\n\n**What**\n\nBash is the tool Claude uses to run shell commands. Commands often end with `| tail`, which keeps only the last lines of output. Claude Code now handles this:\n\n- When a command pipes into tail, a saved copy of the full output is kept. Bash results gain `tailInputPath`, the path to that copy, and `tailInputNote`, a note added to the result text Claude sees.\n\n- The shell runner gains a `tailInput` parameter, passed through to `buildExecCommand`, which can now also report `takesTailInput` and `refusedBeforeBash`. This applies on Unix only, outside the sandbox and not on Windows.\n\n- Background shells, commands left running while Claude works, gained an optional `atEnd` step. It can hold the task, ask something at the end with a time limit, and add the answer as an `endNote` to the notice Claude gets when the task finishes, including a final-response notice.\n\n- Completed background tasks can show a note and say \"Output\" rather than \"Full output\".\n\n- Separately, the `ScheduleWakeup` tool no longer requires a `noop` argument.\n\nThe stock descriptions of `Bash` and `ScheduleWakeup`, captured under this release, are unchanged.\n\n**Why**\n\nIf a command cut its output short with tail, Claude can now go back to the saved copy instead of running the command again. What Claude is told when a background command ends may also include an extra note.\n\n- Area: Bash\n- Tier: You'll notice\n- Useful: 3\/5\n- Signal: 3\/5\n- Scope: individual\n- Heads-up: no"}