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Full Discussion: Why is ./ sometimes needed?
Top Forums Shell Programming and Scripting Why is ./ sometimes needed? Post 303029723 by wisecracker on Thursday 31st of January 2019 07:21:32 AM
Old 01-31-2019
Thanks Don...

There is this however, reference to OSX 10.14.1, default bash terminal:
Code:
Last login: Thu Jan 31 12:05:01 on ttys000
AMIGA:amiga~> man true
AMIGA:amiga~> help true
true: true
    Return a successful result.
AMIGA:amiga~> man false
AMIGA:amiga~> help false
false: false
    Return an unsuccessful result.
AMIGA:amiga~> man :
No manual entry for :
AMIGA:amiga~> help :
:: :
    No effect; the command does nothing.  A zero exit code is returned.
AMIGA:amiga~> 
AMIGA:amiga~> which true
/usr/bin/true
AMIGA:amiga~> which false
/usr/bin/false
AMIGA:amiga~> which :
AMIGA:amiga~> _

Both XUbuntu56 and I can learn from your expertise on this.
I have not copied and pasted the man pages but they do exist.

As you can see there is a manual AND a help entry for "true" and "false", do I take it the some shells, perhaps dash or ash, do not have these as builtins as it looks like I have both builtin and transient versions.
":" is builtin only so I assume that in POSIX this IS a requirement but the others are optional?

TIA.

Bazza...
 

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true(1) 						      General Commands Manual							   true(1)

NAME
true, false - Returns a standard exit value SYNOPSIS
true false STANDARDS
Interfaces documented on this reference page conform to industry standards as follows: true: XCU5.0 false: XCU5.0 Refer to the standards(5) reference page for more information about industry standards and associated tags. DESCRIPTION
The true command returns a 0 (zero) exit value. The false command returns a nonzero exit value. These commands are usually used in input to shell commands. NOTES
The special built-in utility : (colon) is sometimes more efficient than the true command. EXIT STATUS
[Tru64 UNIX] The nonzero value returned by the false command may vary from system to system. EXAMPLES
To construct a loop in a shell procedure, enter: while true do date sleep 60 done This procedure displays the date and time once a minute. To stop it, press the Interrupt key sequence. SEE ALSO
Commands: csh(1), ksh(1), Bourne Shell sh(1b), POSIX shell sh(1p) Standards: standards(5) true(1)
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