shell builtin – commands, that are built into the shell.
and are more often than not shell builtins. Note, that
a command can be available as a shell builtin and as an executable or shell script (see next type).
An example on my system is the command .
compiled executable / shell script – compiled and installed programs. I.e.,
programs in and compiled programs installed in
or somewhere in.
Scripts, that are executed in a shell or an interpreter like Perl,
which is available in most Linux systems in .
shell alias – aliases for commands that are defined in .
shell function – shell functions that are sourced (read) in .
checking command type with type
To check the type of a command, run , i.e. .
The following section lists the output of for the four types of shell
commands listed above.
shell builtin
general form
<command> is a shell builtin
example
rudolf@idoru:~$ type test
test is a shell builtin
rudolf@idoru:~$
compiled executable / shell script
general form
<command> is <path to command executable>
example
rudolf@idoru:~$ type ssh
ssh is /usr/bin/ssh
rudolf@idoru:~$
shell alias
general form
<command> is aliased to <alias definition in .bashrc>
example
rudolf@idoru:~$ type ls
ls is aliased to `ls --color=auto'
rudolf@idoru:~$
shell function
general form
<command> is a function
example
rudolf@idoru:~$ type javaversion
javaversion is a function
javaversion ()
{
javaDir=/opt/sys/vm;
versions=/opt/sys/vm/vm-versions;
. ${versions};
## rest of function omitted here for brevity
return ${errcode}
}
rudolf@idoru:~$