Help in explaining this echo conundrum. Post: 302993810

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Operating Systems OS X (Apple) Help in explaining this echo conundrum. Post 302993810 by wisecracker on Tuesday 14th of March 2017 03:39:45 PM

03-14-2017

Registered User

@ Scrutinizer...

Also interestingly when using 'dash' on OSX 10.12.3 default bash terminal:-

Code:

Last login: Tue Mar 14 18:32:20 on ttys000
AMIGA:amiga~> /usr/local/bin/dash
AMIGA:\u\w> echo '1\n2\n3\n4\n5' > /tmp/text
AMIGA:\u\w> hexdump -C /tmp/text
00000000  31 0a 32 0a 33 0a 34 0a  35 0a                    |1.2.3.4.5.|
0000000a
AMIGA:\u\w> /bin/echo '1\n2\n3\n4\n5' > /tmp/text
AMIGA:\u\w> hexdump -C /tmp/text
00000000  31 5c 6e 32 5c 6e 33 5c  6e 34 5c 6e 35 0a        |1\n2\n3\n4\n5.|
0000000e
AMIGA:\u\w> exit
AMIGA:amiga~> _

Seems consistent with 'sh'.
I am going to have to be careful with this.

---------- Post updated at 07:39 PM ---------- Previous update was at 07:10 PM ----------

Quote:

Originally Posted by Corona688

'echo' is not consistent or portable between different shells. Sometimes you get newlines, sometimes you get \n, sometimes you only get newlines when you ask for them with echo -e, and sometimes you can't get newlines out no matter what you do (i.e. /bin/sh on solaris). Given OSX's nextstep/mach lineage, I'll wild-guess that their /bin/sh is meant to resemble an old Bourne from BSD.

printf is a lot more consistent.

I do know a few ideas but do not know if this would work in the Solaris situation you quoted.
This is longhand using 'dash' and '/bin/echo'...
You will have to take my word for the 'bold' as it does not copy and paste too well... ;o)

Code:

Last login: Tue Mar 14 19:22:37 on ttys000
AMIGA:amiga~> /usr/local/bin/dash
AMIGA:\u\w> nl='
> '
AMIGA:\u\w> esc=`printf "\033"`
AMIGA:\u\w> /bin/echo '1\n2\n3'
1\n2\n3
AMIGA:\u\w> /bin/echo "1\n2\n3"
1\n2\n3
AMIGA:\u\w> /bin/echo '1${nl}2${nl}3'
1${nl}2${nl}3
AMIGA:\u\w> /bin/echo "1${nl}2${nl}3"
1
2
3
AMIGA:\u\w> # Make characters BOLD...
AMIGA:\u\w> /bin/echo "Normal text, $esc[1mbold text..."
Normal text, bold text...
AMIGA:\u\w> exit
AMIGA:amiga~> _

There are ways to bend rules even in dash...

Last edited by wisecracker; 03-14-2017 at 04:43 PM.. Reason: Sorry about the attachment. I did expect a new window.

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LEARN ABOUT SUNOS

setusershell

getusershell(3C)					   Standard C Library Functions 					  getusershell(3C)

NAME

       getusershell, setusershell, endusershell - get legal user shells

SYNOPSIS

       #include <unistd.h>

       char *getusershell(void);

       void setusershell(void);

       void endusershell(void);

DESCRIPTION

       The  getusershell()  function  returns  a  pointer  to  a  legal  user  shell  as defined by the system manager in the file /etc/shells. If
       /etc/shells does not exist, the following locations of the standard system shells are used in its place:

       /bin/bash		  /bin/csh
       /bin/jsh 		  /bin/ksh
       /bin/pfcsh		  /bin/pfksh
       /bin/pfsh		  /bin/sh
       /bin/tcsh		  /bin/zsh
       /sbin/jsh		  /sbin/pfsh
       /sbin/sh 		  /usr/bin/bash
       /usr/bin/csh		  /usr/bin/jsh
       /usr/bin/ksh		  /usr/bin/pfcsh
       /usr/bin/pfksh		  /usr/bin/pfsh
       /usr/bin/sh		  /usr/bin/tcsh
       /usr/bin/zsh		  /usr/xpg4/bin/sh

       The getusershell() function opens the file /etc/shells, if it exists, and returns the next entry in the list of shells.

       The setusershell() function rewinds the file or the list.

       The endusershell() function closes the file, frees any memory used by getusershell() and setusershell(), and rewinds the file /etc/shells.

RETURN VALUES

       The getusershell() function returns a null pointer on EOF.

BUGS

       All information is contained in memory that may be freed with a call to endusershell(), so it must be copied if it is to be saved.

SunOS 5.10							    30 Aug 2004 						  getusershell(3C)