| `-a` | `allexport` | Automatically mark new and altered variables to be exported to subsequent environments. |
| `-b` | `notify` | Don't wait for the next prompt to print when showing the reports for a terminated background job (only with job control) |
| `-e` | `errexit` | When set, the shell exits when a simple command in a command list exits non-zero (`FALSE`). This is not done in situations, where the exit code is already checked (`if`, `while`, `until`, `||`, `&&`) |
| `-h` | `hashall` | Remembers the location of commands when they're called (hashing). Enabled by default. |
| `-k` | `keyword` | Allows to place environment-assignments everywhere in the commandline, not only infront of the called command. |
| `-m` | `monitor` | **Monitor mode**. With job control, a short descriptive line is printed when a backgroud job ends. Default is "on" for interactive shells (with job control). |
| `-n` | `noexec` | Read and parse but **do not execute commands** - useful for checking scripts for syntax errors. Ignored by interactive shells. |
| `-o` | | Set/unset attributes with long option names, e.g. `set -o noglob`. The long option names are in the second column of this table. If no option name is given, all options are printed with their current status. |
| `-p` | `privileged` | Turn on privileged mode. |
| `-t` | `onecmd` | Exit after reading and executing **one** command. |
| `-u` | `nounset` | Treat unset variables as an error when performing parameter expansion. Non-interactive shells exit on this error. |
| `-v` | `verbose` | Print shell input lines as they are read - useful for debugging. |
| `-x` | `xtrace` | Print commands just before execution - with all expansions and substitutions done, and words marked - useful for debugging. |
| `-B` | `braceexpand` | The shell performs [brace expansion](/syntax/expansion/brace.md) This is on by default. |
| `-C` | \<BOOKMARK:tag_noclobber\>`noclobber` | Don't overwrite files on redirection operations. You can override that by specifying the `>|` redirection operator when needed. See [redirection](/syntax/redirection.md) |
| `-E` | `errtrace` | `ERR`-traps are inherited by by shell functions, command substitutions, and commands executed in a subshell environment. |
| `-H` | `histexpand` | Enable `!`-style history expansion. Defaults to `on` for interactive shells. |
| `-P` | `physical` | Don't follow symlinks when changing directories - use the physical filesystem structure. |
| `-T` | `functrace` | `DEBUG`- and `RETURN`-traps are inherited by subsequent environments, like `-E` for `ERR` trap. |
| `-` | | "End of options" - all following arguments are assigned to the positional parameters, even when they begin with a dash. `-x` and `-v` options are turned off. Positional parameters are unchanged (unlike using `--`!) when no further arguments are given. |
| `--` | | If no arguments follow, the positional parameters are unset. With arguments, the positional parameters are set, even if the strings begin with a `-` (dash) like an option. |
| | Long options usable with `-o` without a short equivalent | |
| | `emacs` | Use an emacs-style command line editing interface. This is enabled by default when the shell is interactive, unless the shell is started with `--noediting` option. |
| | `history` | If set, command historization is done (enabled by default on interactive shells) |
| | `pipefail` | If set, the exit code from a pipeline is different from the normal ("last command in pipeline") behaviour: `TRUE` when no command failed, `FALSE` when something failed (code of the rightmost command that failed) |
| | `posix` | When set, Bash runs in POSIX mode. |
| | `vi` | Enables a `vi`-style command line editing interface. |
## Examples
Tag a part of a shell script to output debugging information (`-x`):
``` bash
#!/bin/bash
...
set -x # on
...
set +x # off
...
```
## Portability considerations
`set` and its basic behaviour and options are specified by POSIX(r).
However, options that influence Bash-specific things are not portable,
