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Full Discussion: Discussion: use "/usr/bin/env" or not
Top Forums Shell Programming and Scripting Discussion: use "/usr/bin/env" or not Post 302973179 by drl on Sunday 15th of May 2016 06:32:44 PM
Old 05-15-2016
Hi.

Of the few discussions I have read, I like the one at shell script - Why is it better to use "#!/usr/bin/env NAME" instead of "#!/path/to/NAME" as my shebang? - Unix & Linux Stack Exchange

The main response leans towards the view of Aia and perhaps that of Don Cragun, mentioning the drawbacks. The follow-on responses there (including some from familiar names) illustrate that *nix provides the choice.

Whichever one prefers depends on the goal. As I have said, for me it's portability. I don't have similarly named codes on my systems. I don't have my ~/bin before the system directories. My PATH and root's PATH are the same respectively as possible on systems (Solaris an exception for /opt).

When I have a code that is a work-alike, either I name it differently, or I call it my-code, like my-tac, or my-uniq (too-limited a design for uniq, simple but not flexible enough for me). Currently I have about 40 of those, but for solutions that I provide to others I'm more likely to use standard commands.

The Linux distribution that I use most frequently is GNU/Debian. They seem to often use a scheme for numbering similar interpretors. So python -> python2.7, python3 -> python3.4:
Code:
$ version =o python python2.7
OS, ker|rel, machine: Linux, 3.16.0-4-amd64, x86_64
Distribution        : Debian 8.4 (jessie) 
Python 2.7.9
python2.7 Python 2.7.9

Don's comments reminds me of discussions I had with Sun. I really liked their hardware, and their man pages were very good because they often included examples, but otherwise Sun seemed very resistant to incorporate new features that users wanted or needed. That has changed a bit recently. One can use GNU utilities on (recent) Solaris systems:
Code:
$ version =o patch
OS, ker|rel, machine: SunOS, 5.11, i86pc
Distribution        : Solaris 11.3 X86
patch GNU patch 2.7.5

I'm not so much interested in the same as I am in the best.

Thanks to everyone for their comments ... cheers, drl
 

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LEARN ABOUT SUNOS

env

env(1)								   User Commands							    env(1)

NAME

       env - set environment for command invocation

SYNOPSIS

       /usr/bin/env [-i | -]  [name=value...] [ utility [ arg... ]]

       /usr/xpg4/bin/env [-i | -]  [name=value...] [ utility [ arg... ]]

DESCRIPTION

       The  env utility obtains the current environment, modifies it according to its arguments, then invokes the utility named by the utility op-
       erand with the modified environment.

       Optional arguments are passed to utility. If no utility operand is specified, the resulting environment is written to the standard  output,
       with one name=value pair per line.

   /usr/bin
       If env executes commands with arguments, it uses the default shell /usr/bin/sh (see sh(1)).

   /usr/xpg4/bin
       If env executes commands with arguments, it uses /usr/xpg4/bin/sh (see ksh(1)).

OPTIONS

       The following options are supported:

       -i | -	       Ignores the environment that would otherwise be inherited from the current shell.  Restricts the environment for utility to
		       that specified by the arguments.

OPERANDS

       The following operands are supported:

       name=value      Arguments of the form name=value modify the execution environment, and are placed into  the  inherited  environment  before
		       utility is invoked.

       utility	       The name of the utility to be invoked.  If utility names any of the special shell built-in utilities, the results are unde-
		       fined.

       arg	       A string to pass as an argument for the invoked utility.

EXAMPLES

       Example 1: Invoking utilities with new PATH values

       The following utility:

       example% env -i PATH=/mybin mygrep xyz myfile

       invokes the utility mygrep with a new PATH value as the only entry in its environment. In this case, PATH is used to locate  mygrep,  which
       then must reside in /mybin.

ENVIRONMENT VARIABLES

       See  environ(5)	for  descriptions of the following environment variables that affect the execution of env: LANG, LC_ALL, LC_CTYPE, LC_MES-
       SAGES, and NLSPATH.

       PATH	Determine the location of the utility. If PATH is specified as a name=value operand to env, the value given shall be used  in  the
		search for utility.

EXIT STATUS

       If  utility  is invoked, the exit status of env is the exit status of utility. Otherwise, the env utility returns one of the following exit
       values:

       0	Successful completion.

       1-125	An error occurred.

       126	utility was found but could not be invoked.

       127	utility could not be found.

ATTRIBUTES

       See attributes(5) for descriptions of the following attributes:

   /usr/bin
       +-----------------------------+-----------------------------+
       |      ATTRIBUTE TYPE	     |	    ATTRIBUTE VALUE	   |
       +-----------------------------+-----------------------------+
       |Availability		     |SUNWcsu			   |
       +-----------------------------+-----------------------------+
       |CSI			     |enabled			   |
       +-----------------------------+-----------------------------+

   /usr/xpg4/bin
       +-----------------------------+-----------------------------+
       |      ATTRIBUTE TYPE	     |	    ATTRIBUTE VALUE	   |
       +-----------------------------+-----------------------------+
       |Availability		     |SUNWxcu4			   |
       +-----------------------------+-----------------------------+
       |CSI			     |enabled			   |
       +-----------------------------+-----------------------------+
       |Interface Stability	     |Standard			   |
       +-----------------------------+-----------------------------+

SEE ALSO

       ksh(1), sh(1), exec(2), profile(4), attributes(5), environ(5), standards(5)

SunOS 5.10							    2 Jan 2002								    env(1)
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