How to inspect command before execution

It is nothing fancy, but there are situations where it is beneficial to know how to identify and inspect command before execution.

This can be achieved by using type shell builtin command.

$ type ls
ls is aliased to `ls --color=auto'

$ type quote
quote is a function
quote () 
{ 
    local quoted=${1//\'/\'\\\'\'};
    printf "'%s'" "$quoted"
}

$ type lvm
lvm is /sbin/lvm

Use -t argument to identify command type, which is one of alias, reserved keyword, function, builtin, file.

$ type -t ls
alias

$ type -t case
keyword

$ type -t quote
function

$ type -t type
builtin

$ type -t tar
file

Use -p argument to print filename of the command to be executed.

$ type -p tar
/bin/tar

Use -P argument to force search for the filename of the command to be executed. It is useful in several edge cases (command is alias, function, builtin).

$ type -P ls
/bin/ls

$ type -P pwd
/bin/pwd

Use -a argument to print all information at once.

$ type -a ls
ls is aliased to `ls --color=auto'
ls is /bin/ls

$ type -a pwd
pwd is a shell builtin
pwd is /bin/pwd