# casinh(3) [plan9 man page]

```CASINH(3)						     Linux Programmer's Manual							 CASINH(3)

NAME
casinh, casinhf, casinhl - complex arc sine hyperbolic

SYNOPSIS
#include <complex.h>

double complex casinh(double complex z);
float complex casinhf(float complex z);
long double complex casinhl(long double complex z);

DESCRIPTION
These functions calculate the complex arc hyperbolic sine of z.	If y = casinh(z), then z = csinh(y).  The imaginary part of y is chosen in
the interval [-pi/2,pi/2].

One has:

casinh(z) = clog(z + csqrt(z * z + 1))

VERSIONS
These functions first appeared in glibc in version 2.1.

ATTRIBUTES
For an explanation of the terms used in this section, see attributes(7).

+-------------------------------+---------------+---------+
|Interface		       | Attribute     | Value	 |
+-------------------------------+---------------+---------+
|casinh(), casinhf(), casinhl() | Thread safety | MT-Safe |
+-------------------------------+---------------+---------+
CONFORMING TO
C99, POSIX.1-2001, POSIX.1-2008.

asinh(3), cabs(3), cimag(3), csinh(3), complex(7)

COLOPHON
This page is part of release 4.15 of the Linux man-pages project.  A description of the project, information about reporting bugs, and  the

2015-04-19								 CASINH(3)```

## Check Out this Related Man Page

```CASINH(3)						     Linux Programmer's Manual							 CASINH(3)

NAME
casinh, casinhf, casinhl - complex arc sine hyperbolic

SYNOPSIS
#include <complex.h>

double complex casinh(double complex z);
float complex casinhf(float complex z);
long double complex casinhl(long double complex z);

DESCRIPTION
These functions calculate the complex arc hyperbolic sine of z.	If y = casinh(z), then z = csinh(y).  The imaginary part of y is chosen in
the interval [-pi/2,pi/2].

One has:

casinh(z) = clog(z + csqrt(z * z + 1))

VERSIONS
These functions first appeared in glibc in version 2.1.

ATTRIBUTES
For an explanation of the terms used in this section, see attributes(7).

+-------------------------------+---------------+---------+
|Interface		       | Attribute     | Value	 |
+-------------------------------+---------------+---------+
|casinh(), casinhf(), casinhl() | Thread safety | MT-Safe |
+-------------------------------+---------------+---------+
CONFORMING TO
C99, POSIX.1-2001, POSIX.1-2008.

asinh(3), cabs(3), cimag(3), csinh(3), complex(7)

COLOPHON
This page is part of release 4.15 of the Linux man-pages project.  A description of the project, information about reporting bugs, and  the

2015-04-19								 CASINH(3)```
Man Page

## Shopt -s histappend

What is the point of this? Whenever I close my shell it appends to the history file without adding this. I have never seen it overwrite my history file. # When the shell exits, append to the history file instead of overwriting it shopt -s histappend

## What's your most useful shell?

What's your most useful shell? /bin/sh /bin/csh /bin/ksh /bin/tcsh /bin/bash