exec.md

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

See Also

• Background Process (bg): Run processes in the background
• Check Builtin Exists (bexists): Check which builtins exist
• Define Variable (set): Define a variable (typically local) and set it's value
• Display Running Functions (fid-list): Lists all running functions within the current Murex session
• Display Running Functions (jobs): Lists all running functions within the current Murex session
• Execute Shell Function or Builtin (fexec): Execute a command or function, bypassing the usual order of precedence.
• Foreground Process (fg): Sends a background process into the foreground
• Kill All In Session (fid-killall): Terminate all running Murex functions in current session
• Kill Function (fid-kill): Terminate a running Murex function
• Re-Scan $PATH For Executables: Forces Murex to rescan $PATH looking for executables
• Shell Runtime (builtins): Returns runtime information on the internal state of Murex

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This document was generated from builtins/core/typemgmt/types_doc.yaml.