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Suppose I want a bash command to do something extra. As a simple example, imagine I just want it to echo "123" before running.

One simply way to do this would be to alias the command. Since we still need the original, we can just refer to it by its exact path, which we can find using which. For example:

$ which rm
/bin/rm
$ echo "alias rm='echo 123 && /bin/rm'" >> .bashrc

This was easy because I was able to look up the path to rm using which.

However, I am trying to do this with exit, and which doesn't seem to know anything about it.

$ which exit
$ echo $?
1

The command did not output a path, and in fact it returned a non-zero exit code, which which does when a command is not in $PATH.

I thought maybe it's a function, but apparently that's not the case either:

$ typeset -F | grep exit
$ echo $?
1

So the exit command is not defined anywhere as a function or as a command in $PATH, and yet, when I type exit, it closes the terminal. So it clearly is defined somewhere but I can't figure out where.

Where is it defined, and how can I refer to it explicitly?

Suppose I want a bash command to do something extra. As a simple example, imagine I just want it to echo "123" before running.

One simply way to do this would be to alias the command. Since we still need the original, we can just refer to it by its exact path, which we can find using which. For example:

$ which rm
/bin/rm
$ echo "alias rm='echo 123 && /bin/rm'" >> .bashrc

This was easy because I was able to look up the path to rm using which.

However, I am trying to do this with exit, and which doesn't seem to know anything about it.

$ which exit
$ echo $?
1

The command did not output a path, and in fact it returned a non-zero exit code, which which does when a command is not in $PATH.

I thought maybe it's a function, but apparently that's not the case either:

$ typeset -F | grep exit
$ echo $?
1

So the exit command is not defined anywhere as a function or as a command in $PATH, and yet, when I type exit, it closes the terminal. So it clearly is defined somewhere but I can't figure out where.

Where is it defined, and how can I call to it explicitly?

Suppose I want a bash command to do something extra. As a simple example, imagine I just want it to echo "123" before running.

One simply way to do this would be to alias the command. Since we still need the original, we can just refer to it by its exact path, which we can find using which. For example:

$ which rm
/bin/rm
$ echo "alias rm='echo 123 && /bin/rm'" >> .bashrc

This was easy because I was able to look up the path to rm using which.

However, I am trying to do this with exit, and which doesn't seem to know anything about it.

$ which exit
$ echo $?
1

The command did not output a path, and in fact it returned a non-zero exit code, which which does when a command is not in $PATH.

I thought maybe it's a function, but apparently that's not the case either:

$ typeset -F | grep exit
$ echo $?
1

So the exit command is not defined anywhere as a function or as a command in $PATH, and yet, when I type exit, it closes the terminal. So it clearly is defined somewhere but I can't figure out where.

Where is it defined?

Suppose I want a bash command to do something extra. As a simple example, imagine I just want it to echo "123" before running.

One simply way to do this would be to alias the command. Since we still need the original, we can just refer to it by its exact path, which we can find using which. For example:

$ which rm
/bin/rm
$ echo "alias rm='echo 123 && /bin/rm'" >> .bashrc

This was easy because I was able to look up the path to rm using which.

However, I am trying to do this with exit, and which doesn't seem to know anything about it.

$ which exit
$ echo $?
1

The command did not output a path, and in fact it returned a non-zero exit code, which which does when a command is not in $PATH.

I thought maybe it's a function, but apparently that's not the case either:

$ typeset -F | grep exit
$ echo $?
1

So the exit command is not defined anywhere as a function or as a command in $PATH, and yet, when I type exit, it closes the terminal. So it clearly is defined somewhere but I can't figure out where.

Where is it defined, and how can I refer to it explicitly?

Suppose I want a bash command to do something extra. As a simple example, imagine I just want it to echo "123" before running.

One simply way to do this would be to alias the command. Since we still need the original, we can just refer to it by its exact path, which we can find using which. For example:

$ which rm
/bin/rm
$ echo "alias rm='echo 123 && /bin/rm'" >> .bashrc

This was easy because I was able to look up the path to rm using which.

However, I am trying to do this with exit, and which doesn't seem to know anything about it.

$ which exit
$ echo $?
1

The command did not output a path, and in fact it returned a non-zero exit code, which which does when a command is not in $PATH.

I thought maybe it's a function, but apparently that's not the case either:

$ typeset -F | grep exit
$ echo $?
1

So the exit command is not defined anywhere as a function or as a command in $PATH, and yet it works. How is that possible? Where is it defined?

Suppose I want a bash command to do something extra. As a simple example, imagine I just want it to echo "123" before running.

One simply way to do this would be to alias the command. Since we still need the original, we can just refer to it by its exact path, which we can find using which. For example:

$ which rm
/bin/rm
$ echo "alias rm='echo 123 && /bin/rm'" >> .bashrc

This was easy because I was able to look up the path to rm using which.

However, I am trying to do this with exit, and which doesn't seem to know anything about it.

$ which exit
$ echo $?
1

The command did not output a path, and in fact it returned a non-zero exit code, which which does when a command is not in $PATH.

I thought maybe it's a function, but apparently that's not the case either:

$ typeset -F | grep exit
$ echo $?
1

So the exit command is not defined anywhere as a function or as a command in $PATH, and yet, when I type exit, it closes the terminal. So it clearly is defined somewhere but I can't figure out where.

Where is it defined?