> ## Documentation Index
> Fetch the complete documentation index at: https://docs.syntblaze.com/llms.txt
> Use this file to discover all available pages before exploring further.
# Bash Shift Command
The `shift` command is a Bash shell builtin that reassigns the positional parameters by shifting them to the left. When executed, the value of the positional parameter `$n+1` is assigned to `$1`, `$n+2` is assigned to `$2`, and so forth. This operation permanently discards the first *n* positional parameters from the current shell execution context and decrements the total parameter count (`$#`) by *n*.
```bash theme={"dark"}
shift [n]
```
## Mechanics and State Changes
* **Argument `n`:** An optional non-negative integer dictating the shift offset.
* **Default Behavior:** If `n` is omitted, the command defaults to `shift 1`. If `n` is `0`, no parameters are modified.
* **Immutability of `$0`:** The special parameter `$0` (the script or shell name) is strictly excluded from the shift operation and remains unchanged.
* **Parameter Count (`$#`):** The variable `$#` is dynamically updated to equal `$# - n`.
* **Unsetting Parameters:** The highest *n* positional parameters that previously held values are unset.
## Exit Status
* **`0` (Success):** The shift operation completes successfully, meaning `n` was less than or equal to `$#`.
* **`>0` (Failure):** If `n` is strictly greater than the current number of positional parameters (`$#`), the command fails. In this state, no positional parameters are modified, and `$#` remains unchanged.
## State Visualization
```bash theme={"dark"}
# Initial execution state: ./script.sh alpha bravo charlie delta echo
# $0 = "./script.sh"
# $1 = "alpha"
# $2 = "bravo"
# $3 = "charlie"
# $4 = "delta"
# $5 = "echo"
# $# = 5
shift 2
# Post-shift execution state:
# $0 = "./script.sh" (Unchanged)
# $1 = "charlie" (Previously $3)
# $2 = "delta" (Previously $4)
# $3 = "echo" (Previously $5)
# $4 = unset
# $5 = unset
# $# = 3 (Decremented by 2)
```
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