Execute External Command (exec)

Laurence MorganAbout 2 minBuiltin CommandsProcess Management

Execute External Command (`exec`)

Runs an executable

Description

With Murex, like most other shells, you launch a process by calling the name of that executable directly. While this is suitable 99% of the time, occasionally you might run into an edge case where that wouldn't work. The primary reason being if you needed to launch a process from a variable, eg

» set exe=uname
» $exe
uname

As you can see here, Murex's behavior here is to output the contents of the variable rather then executing the contents of the variable. This is done for safety reasons, however if you wanted to override that behavior then you could prefix the variable with exec:

» set exe=uname
» exec $exe
Linux

Usage

<stdin> -> exec

<stdin> -> exec -> <stdout>

           exec -> <stdout>

Examples

As a function

» exec printf "Hello, world!"
Hello, world!

Working around aliases

If you have an alias like alias ls=ls --color=auto and you wanted to run ls but without colour, you might run exec ls.

Detail

If any command doesn't exist as a builtin, function nor alias, then Murex will default to forking out to any command with this name (subject to an absolute path or the order of precedence in $PATH). Any forked process will show up in both the operating systems process viewer (eg ps) but also Murex's own process viewer, fid-list. However inside fid-list you will notice that all external processes are listed as exec with the process name as part of exec's parameters. That is because exec is handler for programs that aren't native to Murex.

Compatibility with POSIX

For compatibility with traditional shells like Bash and Zsh, command is an alias for exec.

Synonyms

exec
command
exec.file

Execute External Command (exec)

# Execute External Command (exec)

# Description

# Usage

# Examples

# As a function

# Working around aliases

# Detail

# Compatibility with POSIX

# Synonyms

# See Also