There is no requirement in the standards saying that utilities found in /bin conform to the standard. The only files that the POSIX standards require to be at a specific location are /, /dev, /dev/console, /dev/null, /dev/tty, and /tmp.
The 2nd example in the EXAMPLES section on the POSIX command utility man page shows you how to start a POSIX script that will use the "standard" utilities when referenced by name assuming that you are running a POSIX conforming shell. And, if you can find a POSIX conforming command utility (note that command is almost always a shell built-in in a standards conforming shell, but there must also be a standalone command utility) the command:
will give you the pathname on your system of a POSIX conforming version of the utility named standard_utility_name in any shell.
These 2 Users Gave Thanks to Don Cragun For This Post:
Hi
How to call a shell scripting through a Perl scripting? Actually I need some value from Shell scripting and passes in the Perl scripting. So how can i do this? (2 Replies)
Hi all,
I would like to start developping some good scripting skills. Do you think it would be best to start with shell scripting or Perl? I already got a fundation, really basics, in perl. but I am wondering what would be best to be good at first.
Can you please help me determine which one to... (14 Replies)
A file contains: abcdef
I need : a b c d e f
It's easy with sed
sed 's/./& /g'but this is embedded linux that doesn't have sed/awk. The shell is unknown but it's bashlike. Parameter expansion works and seems promising and. A question mark seems to work as a wildcard, but there doesn't seem... (5 Replies)
Hi,
i want to check if a variable var1 is not a or b or c
pseudo code:
If NOT (var1 = a or var1 = b or var1 = c)
then
...
fi
I want to use POSIX complaint Korn shell, and for string comparison
For the following code, logical.sh
#!/usr/bin/ksh
var="j"
echo "Var : $var"
if ! { || ||... (12 Replies)
The POSIX shell standard grammar rules are at
Shell Command Language
I am trying to understand Rule 7 and I don't. I think there may be some mistakes there. I am not complaining about the standard; rather, I am concerned that my perception is wrong, and I don't understand something important.... (3 Replies)
Not even thinking that POSIX-Shell is deprecated, but I like working with bash very much, because of it's increased comfort and advanced functions. And in my world here it's available everywhere as default.
Working with kubernetes now, it seems there is a paradigm shift in terms of resources.... (1 Reply)
Hi all,
I am learning POSIX shell programming, and the book I read, uses the let command for integer arithmetic.
I have downloaded and use the shellcheck program on Linux.
This programs says:
In POSIX sh, 'let' is undefined.
See the screenshot attached.
What is the POSIX... (1 Reply)
Hi all...
This is just a fun project to see if it is possible to get a square root of a positive integer from 1 to 9200000 to 6 decimal places on a 64 bit architecture machine.
It is coded around dash and the results show the values from 0 to 10000.
Complex numbers can easily be catered for by... (3 Replies)
Hi all...
Apologies for any typos, etc...
This took a while but it didn't beat me...
Although there are many methods of generating random numbers in a POSIX shell this uses integer maths and a simple C source to create an executable to get epoch to microseconds accuracy if it is needed. I take... (8 Replies)
Discussion started by: wisecracker
8 Replies
LEARN ABOUT OSF1
true
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)