Query on decision making... Post: 302475624

Sponsored Content

Top Forums Shell Programming and Scripting Query on decision making... Post 302475624 by biglau on Monday 29th of November 2010 09:48:55 AM

11-29-2010

Registered User

and the following test in bash:
can anyone could explain the differences of the behaviors?

linux-hhaq:/apps/informatica/current/pmserver/tes/scripts # if [[ `echo` ]]; then echo yes; else echo no; fi
no
linux-hhaq:/apps/informatica/current/pmserver/tes/scripts # if [[ `echo aa` ]]; then echo yes; else echo no; fi
yes
linux-hhaq:/apps/informatica/current/pmserver/tes/scripts # if [[ `function_not_defined` ]]; then echo yes; else echo no; fi
yes
linux-hhaq:/apps/informatica/current/pmserver/tes/scripts # function_return1()
> {
> return 1
> }
linux-hhaq:/apps/informatica/current/pmserver/tes/scripts # if [[ `function_return1` ]]; then echo yes; else echo no; fi
no
linux-hhaq:/apps/informatica/current/pmserver/tes/scripts # function_return0() { return 0; }
linux-hhaq:/apps/informatica/current/pmserver/tes/scripts # if [[ `function_return0` ]]; then echo yes; else echo no; fi
no

biglau

View Public Profile for biglau

Find all posts by biglau

6 More Discussions You Might Find Interesting

1. Shell Programming and Scripting

decision, case, it then else?

I'm writing this script in Korn Shell, on AIX. The script will print a log file, and it needs to decide what region it's in before printing. ( the output of db2 "get instance" is either "The current database manager instance is: db2q" or "The current database manager instance is: db2u") ...

2. UNIX for Dummies Questions & Answers

Platform decision

Hi folks First, let me apologize in advance for the long message. I know this will sound like a typical "newbie" message but I am really working to understand the technology in order to make informed decisions. I am currently in the process of evaluating Unix hardware and OS platforms for an...

3. Shell Programming and Scripting

Numerical Decision

I'm tryning to do something like this, I have this file: spaces12tabgoodbye spaces3tabhello I want to copy to another file the lines that have the number above 10... I thought using sort -rn but I don't know how to discard the lines that have the number below 10. Any idea? Thanks

4. Shell Programming and Scripting

shell script with decision making

Hi all I need help for the issue below. I need to create script: FORM_cmd=query || import FORM_command=add FORM_msisdn=389881234567 FORM_provcode=SK FORM_attr=12 FORM_cmd can be "query" or "import" when FORM_cmd="query" then execute -> spdci -cmd $FORM_cmd FORM_cmd when...

5. Shell Programming and Scripting

Regarding a query on making changes to a running script

Hello All, Greetings !! I have a query here to all is as follows: Question: Let's say we are running a script in a UNIX box and we have opened an another session and then made changes in script of some statements NOT to be print some values(just an example) so when I am monitoring the...

6. UNIX for Beginners Questions & Answers

Handling decision making logic

------- Output Screen -------- Choose the option ----------------- 1.Input 2.Output 3.CFT Uniq x.Exit ----------------- 2 Enter the Output flow IDF PBL5572U Enter the Output existing flow IDF PBL5198H sf_PBL5572U.cmd file exist in invalid path or doesn't exist

LEARN ABOUT OPENSOLARIS

noecho

echo(3XCURSES)						  X/Open Curses Library Functions					    echo(3XCURSES)

NAME

       echo, noecho - enable/disable terminal echo

SYNOPSIS

       cc [ flag... ] file... -I /usr/xpg4/include  -L	/usr/xpg4/lib 
	-R  /usr/xpg4/lib  -lcurses  [ library... ]

       c89 [ flag... ] file... -lcurses [ library... ]

       #include <curses.h>

       int echo(void);

       int noecho(void);

DESCRIPTION

       The  echo()  function enables Echo mode for the current screen. The noecho() function disables Echo mode for the current screen. Initially,
       curses software echo mode is enabled and hardware echo mode of the tty driver is disabled. The echo() and noecho() functions control  soft-
       ware echo only. Hardware echo must remain disabled for the duration of the application, else the behavior is undefined.

RETURN VALUES

       Upon successful completion, these functions return OK. Otherwise, they return ERR.

ERRORS

       No errors are defined.

ATTRIBUTES

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

       +-----------------------------+-----------------------------+
       |      ATTRIBUTE TYPE	     |	    ATTRIBUTE VALUE	   |
       +-----------------------------+-----------------------------+
       |Interface Stability	     |Standard			   |
       +-----------------------------+-----------------------------+
       |MT-Level		     |Unsafe			   |
       +-----------------------------+-----------------------------+

SEE ALSO

       getch(3XCURSES), getstr(3XCURSES), initscr(3XCURSES), libcurses(3XCURSES), scanw(3XCURSES), attributes(5), standards(5)

SunOS 5.11							    5 Jun 2002							    echo(3XCURSES)