Yes. Forking is spelled &:

echo child & echo parent 

What may be confusing you is that $$ is not the PID of the shell process, it's the PID of the original shell process. The point of making it this way is that $$ is a unique identifier for a particular instance of the shell script: it doesn't change during the script's execution, and it's different from $$ in any other concurrently running script. One way to get the shell process's actual PID is sh -c 'echo $PPID'.

The control flow in the shell isn't the same as C. If in C you'd write

first(); fork(); second(); third(); 

then a shell equivalent is

after_fork () { second; third; } first; after_fork & after_fork 

The simple shell form first; parent & child corresponds to the usual C idiom

first(); if (fork()) parent(); else child(); 

& and $$ exist and behave this way in every Bourne-style shell and in (t)csh. $PPID didn't exist in the orignal Bourne shell but is in POSIX (so it's in ash, bash, ksh, zsh, …).

Yes. Forking is spelled &:

echo child & echo parent 

What may be confusing you is that $$ is not the PID of the shell process, it's the PID of the original shell process. The point of making it this way is that $$ is a unique identifier for a particular instance of the shell script: it doesn't change during the script's execution, and it's different from $$ in any other concurrently running script. One way to get the shell process's actual PID is sh -c 'echo $PPID'.

The control flow in the shell isn't the same as C. If in C you'd write

first(); fork(); second(); third(); 

then a shell equivalent is

after_fork () { second; third; } first; after_fork & after_fork 

The simple shell form first; child & parent corresponds to the usual C idiom

first(); if (fork()) parent(); else child(); 

& and $$ exist and behave this way in every Bourne-style shell and in (t)csh. $PPID didn't exist in the orignal Bourne shell but is in POSIX (so it's in ash, bash, ksh, zsh, …).

Yes. Forking is spelled &:

echo child & echo parent 

What's confusing you is that $$ is not the PID of the shell process, it's the PID of the original shell process. The point of making it this way is that $$ is a unique identifier for a particular instance of the shell script: it doesn't change during the script's execution, and it's different from $$ in any other concurrently running script.

  One way to get the shell process's actual PID is sh -c 'echo $PPID'.

& and $$ exist and behave this way in every Bourne-style shell and in (t)csh. $PPID didn't exist in the orignal Bourne shell but is in POSIX (so it's in ash, bash, ksh, zsh, …).

Yes. Forking is spelled &:

echo child & echo parent 

What may be confusing you is that $$ is not the PID of the shell process, it's the PID of the original shell process. The point of making it this way is that $$ is a unique identifier for a particular instance of the shell script: it doesn't change during the script's execution, and it's different from $$ in any other concurrently running script. One way to get the shell process's actual PID is sh -c 'echo $PPID'.

The control flow in the shell isn't the same as C. If in C you'd write

first(); fork(); second(); third(); 

then a shell equivalent is

after_fork () { second; third; } first; after_fork & after_fork 

The simple shell form first; parent & child corresponds to the usual C idiom

first(); if (fork()) parent(); else child(); 

& and $$ exist and behave this way in every Bourne-style shell and in (t)csh. $PPID didn't exist in the orignal Bourne shell but is in POSIX (so it's in ash, bash, ksh, zsh, …).