IF statement with square brackets Post: 302983621

Sponsored Content

Top Forums Shell Programming and Scripting IF statement with square brackets Post 302983621 by mad man on Friday 14th of October 2016 02:41:49 AM

10-14-2016

Registered User

IF statement with square brackets

Hi All,

Hope you all are doing good. Yesterday in my project i came across a scenario which i can not guess why it was working in one region and why it was not in another region. Please find my issue below.

I am using AIX version 6.0 of UNIX in my project, in shell scripting i have the following code to check if a file exists in a directory or not.

Code:

       
if [ -f $com_dir/$dup_file_name_chk ] || 
[ -f $save_dir/$dup_file_name_chk ]
then
.
.
.
fi

I tested this code in the development region every thing went fine and moved the code to QA there also testing went fine. After 2 successful tests the code was moved to UAT region, my onsite manager tested it in UAT and found this is not working, the file existence was not detected there and testing failed.

After this i doubted this if condition and made it like below.

Code:

       
if [[ -f $com_dir/$dup_file_name_chk ]] || 
[[ -f $save_dir/$dup_file_name_chk ]]
then
.
.
.
fi

Now the same was tested in dev, QA & UAT regions. Now this file existence check was working in UAT region.

Can anyone explain what made this '[[' double brackets to work in the UAT region instead of '[' single bracket. What is the difference between them?
Also why regions differ(single brackets working in dev & QA not in UAT).

mad man

View Public Profile for mad man

Find all posts by mad man

10 More Discussions You Might Find Interesting

1. UNIX for Dummies Questions & Answers

square brackets

I would like to substitute a phrase which contains square brackets. change TO how? Thanks

2. Shell Programming and Scripting

WHy the double square brackets?

One of the senior administrators gave me a shell script to modify and it begins as follows: if ] && ] {more code follows} Why the double square brackets?

3. Shell Programming and Scripting

Double square brackets question

Hi, I just came across an interesting shell script syntax like the one below: ] && (trap 'rm -rf ${WORK_DIR}/*.$$; echo "\n\nInterrupted !!\n\n"; exit 4' 1 2 3 15) Can someone please explain the code snippet above? The trap command bit is fine but ] && is the hazy part. Generally we use an...

4. UNIX for Dummies Questions & Answers

Test command - Two square brackets

Hello, Can someone please explain to me the following line, ] && break I do not understand why two test square brackets are used. Thanks, Shantanu ---------- Post updated at 03:38 PM ---------- Previous update was at 03:35 PM ---------- And, also why there's a $ before (echo $c |...

5. Shell Programming and Scripting

Replacing text between two square brackets

hi guys, i'm writing a script that looks for a unquie id in a file and replaces a string between two square brackets on the same line as the unquie id: ....... ....... 0001 zz 43242 replace this text] name 0002 sd 65466 UK] country ....... ....... how can i find line with id 0001...

6. Shell Programming and Scripting

Delete text between square brackets and also delete those square brackets using sed or awk

Hi All, I have a text file which looks like this: computer programming systems engineering I want to get rid of these square brackets and also the text that is inside these brackets. So that my final text file looks like this: computer programming systems engineering I am using...

7. Shell Programming and Scripting

Extract text between two square [..] brackets

Hi All, After searching about this, I could find some solutions but I am not sure why it is not working in my case. I have a text file with contents between two square brackets. The text file looks like this: Use tags when you post any code so others can easily read your code. You can...

8. UNIX for Dummies Questions & Answers

Single or double square brackets

Hi frieds, I don't understand the difference between single square bracket and double square brackets in a IF condition. Ex. if ; then RETURNJOB=1 else RETURNJOB=0 fi It run, but this if ]; then RETURNJOB=1 else RETURNJOB=0 fi

9. Shell Programming and Scripting

Grep number between Square [] brackets

I wanted to store the number inside the square bracket between colon( : ) and closing suqre bracket(]) in some variable. Suppose I have lines like : Input file : 20140320 00:08:23.846 INFO 84] - anything in line 20140320 00:08:23.846 Test 589] - Virtual and lab lab anything...

10. Shell Programming and Scripting

Problem with occurence of square brackets

Hello all, I have the following problem: $ cat infile this is spam and i need this too this is spam and i need this too $ perl -nwe '$_ =~ /]+ \]+)\]\]*\]? (\+)$/; print "$1 - $2\n";' infile i need this - too i need this - and i need this too I am not sure how many occurences of...

LEARN ABOUT DEBIAN

keynav

KEYNAV(1)						      General Commands Manual							 KEYNAV(1)

NAME

       keynav - a keyboard-driven mouse cursor mover

SYNOPSIS

       keynav

DESCRIPTION

       Keynav  makes  your  keyboard a fast mouse cursor mover. You can move the cursor to any point on the screen with a few key strokes. It also
       simulates mouse click. You can do everything mouse can do with a keyboard.

HOW TO USE

       Run keynav, and activate it by pressing Ctrl+; (semicolon).  You should see a thin frame on the screen with a cross in it.

       Default configuration:

	* h	   : select the left half of the region
	* j	   : select the bottom half of the region
	* k	   : select the top half of the region
	* l	   : select the right half of the region
	* Shift+h  : move the region left
	* Shift+j  : move the region down
	* Shift+k  : move the region up
	* Shift+l  : move the region right
	* Semicolon: move the cursor to the center of the selected region
	* Spacebar : move the cursor and left-click
	* Escape   : cancel the move

CONFIGURATION

       You can configure your own key setting. There is an example in /usr/share/doc/keynav/keynavrc. Copy it to $HOME/.keynavrc and  edit  it	as
       you like.

CONFFILE COMMANDS

	* start        : activate keynav
	* end	       : deactivate keynav
	* cut-left     : select the left half of the region
	* cut-right    : select the right half of the region
	* cut-up       : select the top half of the region
	* cut-down     : select the bottom half of the region
	* move-left    : move the region left
	* move-right   : move the region right
	* move-up      : move the region up
	* move-down    : move the region down
	* warp	       : move the cursor to the center of the selected region
	* click 1      : left-click
	* click 2      : middle-click
	* click 3      : right-click
	* doubleclick 1: left-click twice quickly
	* doubleclick 2: middle-click twice quickly
	* doubleclick 3: right-click twice quickly
	* drag <button> [keyseq]: toggle dragging mode for the given button
				  Example: "drag 1 alt" to do a alt+click-drag
	* grid <rows>x<columns> : change the grid layout of the selection
				  Example: "grid 2x3" to cut screen to 6 cells
	* cell-select <row>x<column>: select a specific cell in the grid
	* cell-select <cell>	    : select a specific cell in the grid

AUTHOR

       keynav was written by Jordan Sissel <jls@semicomplete.com>.

       This manual page was written by Wen-Yen Chuang <caleb@calno.com>, for the Debian project (but may be used by others).

																	 KEYNAV(1)