Sponsored Content
Top Forums UNIX for Dummies Questions & Answers Understanding Code in IF LOOP Post 302328868 by Ariean on Thursday 25th of June 2009 10:47:59 AM
Old 06-25-2009
Understanding Code in IF LOOP

Hello All,

I would like to know and understand the difference between the below 3 IF loops and also if possible what are the different other parameters i could use other than those mentioed in the below lF LOOP conditions, appreciate your help.

Quote:
if [ $? -ne 0 ] ; then
...some statements
fi
Quote:
if [ $? -eq 0 ] ; then
...some statements
fi
Quote:
if [ $# -eq 3 ] ;then
...some statements
fi
Thanks,
Sam.
 

10 More Discussions You Might Find Interesting

1. UNIX for Dummies Questions & Answers

Little Trouble Understanding some code...

Couple of questions as I try to decipher someones code who left... What would something coded like this do? IFS=: grep FIELD1 /Path/Path2/Param.fle | read LBL1 LBL2 USRID EADR SUBJ SERVERNAME CFGTBL DIR ERR=0 Param.fle contents.. FIELD1:FEI::FIELD2:dATAFIELD BATCH:MAIN SERVER......etc.. (2 Replies)
Discussion started by: NycUnxer
2 Replies

2. Shell Programming and Scripting

Need help in understanding thisperl code.

Can any body explains the under given lines of code i have difficulties in understanding it, my $errorlog = "/var/log/controler.log"; &initLanguage($language); &launchCbox(); sub launchCbox { ... (1 Reply)
Discussion started by: Raheel Hassan
1 Replies

3. Shell Programming and Scripting

Problems understanding example code

I am really new to UNIX and programming in general and so apologies if this thread is a bit simple. I have searched and found a piece of sample code for a training program I am currently undertaking, but seeing as I am relatively new, I dont completely understand how it works. Here is the... (1 Reply)
Discussion started by: Makaer
1 Replies

4. UNIX for Dummies Questions & Answers

Problems understanding example code

I am really new to UNIX and programming in general and so apologies if this thread is a bit simple. I have searched and found a piece of sample code for a training program I am currently undertaking, but seeing as I am relatively new, I dont completely understand how it works. Here is the... (6 Replies)
Discussion started by: Makaer
6 Replies

5. UNIX Desktop Questions & Answers

Understanding the code

hello all, May i know what is this "DEBUG_ME $DEBUG_CMD main" doing in the below code. I am confused with alias also "alias DEBUG_ME='#'". Thanks for your help. set -x alias DEBUG_ME='#' if ; then . /product/apps/informatica/v7/pc/ExtProc/debug.ksh "$1" fi # Declaring the... (1 Reply)
Discussion started by: Ariean
1 Replies

6. Shell Programming and Scripting

Help understanding Perl code.

Well, I found myself trying to fix some Perl code (Ive never done any Perl in my life) and I pinpointed the place where the bug could be. But to be sure I have to know what does a few line of code mean: $files_lim =~ (/^\d*$/) $files_lim =~ (/^\d*h$/)$files_age =~ s/h//The code where this was... (0 Replies)
Discussion started by: RedSpyder
0 Replies

7. Programming

Understanding perl code

What is the difference between the two statements below? A: $a->{"$fruit"}->{"$color"}->{size} = $size B: $size = $a->{"$fruit"}->{"$color"}->{size} Please assist. Thanks! (0 Replies)
Discussion started by: onlinelearner02
0 Replies

8. Shell Programming and Scripting

Help with perl code understanding

Hi, I need to understand below perl code, can some one advise me. perl -MDate::Parse -e'BEGIN{$main::now=time;$main::old=(time-60*30)}' -nE'if(/^(\w+\s+\d+\s+\d+:\d+:\d+)/) {$t=str2time $1; $t > $old && $t < $now && print}' (1 Reply)
Discussion started by: learnbash
1 Replies

9. Shell Programming and Scripting

[Solved] Help understanding this code!!

Hi guys, I am still learning awk and much apprecated to shed some light on the following: the questions asked is below! { total = i = 0 do { ++i total += $i } while ( total <= 100 ) print i, ":", total } File used: cat test.do 45 25 60 20 10 105 50 40 33 5 9 67 108 3 5 4 (2 Replies)
Discussion started by: Apollo
2 Replies

10. UNIX for Dummies Questions & Answers

Understanding bash code

I am not able to understand below line in unix bash shell.Could anyone explain what it will do result="${path1}/*${var1}*${var2}*wssreligibleitem*.csv" path1 is defined and it is a directory path var1 is defined and it holds string value like abc var2 is defined and it holds string value like... (6 Replies)
Discussion started by: vamsi.valiveti
6 Replies
SHELL-QUOTE(1)						User Contributed Perl Documentation					    SHELL-QUOTE(1)

NAME
shell-quote - quote arguments for safe use, unmodified in a shell command SYNOPSIS
shell-quote [switch]... arg... DESCRIPTION
shell-quote lets you pass arbitrary strings through the shell so that they won't be changed by the shell. This lets you process commands or files with embedded white space or shell globbing characters safely. Here are a few examples. EXAMPLES
ssh preserving args When running a remote command with ssh, ssh doesn't preserve the separate arguments it receives. It just joins them with spaces and passes them to "$SHELL -c". This doesn't work as intended: ssh host touch 'hi there' # fails It creates 2 files, hi and there. Instead, do this: cmd=`shell-quote touch 'hi there'` ssh host "$cmd" This gives you just 1 file, hi there. process find output It's not ordinarily possible to process an arbitrary list of files output by find with a shell script. Anything you put in $IFS to split up the output could legitimately be in a file's name. Here's how you can do it using shell-quote: eval set -- `find -type f -print0 | xargs -0 shell-quote --` debug shell scripts shell-quote is better than echo for debugging shell scripts. debug() { [ -z "$debug" ] || shell-quote "debug:" "$@" } With echo you can't tell the difference between "debug 'foo bar'" and "debug foo bar", but with shell-quote you can. save a command for later shell-quote can be used to build up a shell command to run later. Say you want the user to be able to give you switches for a command you're going to run. If you don't want the switches to be re-evaluated by the shell (which is usually a good idea, else there are things the user can't pass through), you can do something like this: user_switches= while [ $# != 0 ] do case x$1 in x--pass-through) [ $# -gt 1 ] || die "need an argument for $1" user_switches="$user_switches "`shell-quote -- "$2"` shift;; # process other switches esac shift done # later eval "shell-quote some-command $user_switches my args" OPTIONS
--debug Turn debugging on. --help Show the usage message and die. --version Show the version number and exit. AVAILABILITY
The code is licensed under the GNU GPL. Check http://www.argon.org/~roderick/ or CPAN for updated versions. AUTHOR
Roderick Schertler <roderick@argon.org> perl v5.16.3 2010-06-11 SHELL-QUOTE(1)
All times are GMT -4. The time now is 04:35 AM.
Unix & Linux Forums Content Copyright 1993-2022. All Rights Reserved.
Privacy Policy