Sponsored Content
Top Forums Shell Programming and Scripting Best practice for bracket comparisons? Post 302386535 by Corona688 on Tuesday 12th of January 2010 04:42:10 PM
Old 01-12-2010
Quote:
Originally Posted by tlarkin
Thanks for your reply, but still got a few questions...

According to this document, which I have used to teach myself shell programming, [[ and [ have different abilities in bash.
Yes, BASH has many extensions on the standard shell. But you can't depend on those extensions anywhere else.

As for numerical and string equality being identical, well -- given the same number base and no leading zeroes or extraneous sign symbols, a string comparison is no different than a numerical comparison. I've tried various things to trip them up, things like comparing positive and negative zero... it always acts just like a string comparison whether its one or two equals.
 

10 More Discussions You Might Find Interesting

1. UNIX for Dummies Questions & Answers

Can grep do numerical comparisons?

Say for example I have a list of numbers.. 5 10 13 48 1 could I use grep to show only those numbers that are above 10? For various reasons I can only use grep... not awk or sed etc. (7 Replies)
Discussion started by: Uss_Defiant
7 Replies

2. Shell Programming and Scripting

numeric range comparisons

I have two files.And a sort of matrix analysis. Both files have a string followed by two numbers: File 1: A 2 7 B 3 11 C 5 10 ...... File 2: X 1 10 Y 3 5 Z 5 9 What I'd like to do is for each set of numbers in the second file indicate if the first or second number (or both) in... (7 Replies)
Discussion started by: dcfargo
7 Replies

3. UNIX for Dummies Questions & Answers

Command comparisons

Hi guys, Im trying to figure out what is the difference between using a | and the command xargs ... examples of usage: 1) ls * | wc -w => this gives you the number of files in the current directory including all subdirectories 2) find . “*.log” | xargs grep ERROR => this gives... (6 Replies)
Discussion started by: avidrunner
6 Replies

4. Shell Programming and Scripting

ksh, difference between double bracket and single bracket

Can somebody tell me the difference between double brackets and single brackets, when doing a test. I have always been acustomed to using single brackets and have not encountered any issues to date. Why would somebody use double brackets. Ie if ] vs if Thanks to... (2 Replies)
Discussion started by: BeefStu
2 Replies

5. Shell Programming and Scripting

String comparisons

Can someone please tell me what is wrong with this stings comparison? #!/bin/sh #set -xv set -u VAR=$(ping -c 5 -w 10 google.com | grep icmp_req=5 | awk '{print $6}') echo I like cookies echo $VAR if "$VAR" == 'icmp_req=5' then echo You Rock else echo You Stink fiThis is the error.... (6 Replies)
Discussion started by: cokedude
6 Replies

6. UNIX for Dummies Questions & Answers

Date comparisons

Hi, I want to perform a simple date comparisons, i.e. select all files modified after a certain date (say 12-feb-2011) I do not have the option of creating a file and using find's -newer option. Any simple way to do this? I can do this by reading the stat command's output and comparing... (10 Replies)
Discussion started by: jawsnnn
10 Replies

7. UNIX for Dummies Questions & Answers

File and if statement comparisons

I'd love to get help on this one please. Ok so say I have a file called README with lines such as this: index:index.html required:file1.1:file2.1:file3.1 I'm having trouble with writing an if statement that compares the items in a list with a file inside README, what I imagine in my head... (7 Replies)
Discussion started by: mistsong1
7 Replies

8. Shell Programming and Scripting

Pair wise comparisons

Hi, I have 25 groups and I need to perform all possible pairwise compariosns between them using the formula n(n-1)/2. SO in my case it will be 25(25-1)/2 which is equal to 300 comparisons. my 25 groups are FG1 FG2 FG3 FG4 FG5 NT5E CD44 CD44 CD44 AXL ADAM19 CCDC80 L1CAM L1CAM CD44... (1 Reply)
Discussion started by: Diya123
1 Replies

9. Shell Programming and Scripting

File comparisons

Hi all, I want to compare two files based on column value Kindly help me a.txt 123,ABCD 456,DEF 789,SDF b.txt 123,KJI 456,LMN 321,MJK 678,KOL Output file should be like Common on both files c.txt 123,ABCD,KJI (8 Replies)
Discussion started by: aaysa123
8 Replies

10. Shell Programming and Scripting

String regex comparisons

Here is the sample code: str1="abccccc" str2="abc?" if ]; then echo "same string" else echo "different string" fi Given that ? implies 0 or 1 match of preceding character, I was expecting the output to be "different string", but I am seeing "same string". Am I not using the... (3 Replies)
Discussion started by: Rameshck
3 Replies
fstrcmp(3)						     Library Functions Manual							fstrcmp(3)

NAME
fstrcmp - fuzzy comparison of two strings SYNOPSIS
#include <fstrcmp.h> #define FSTRCMP_IDENTICAL #define FSTRCMP_THRESHOLD #define FSTRCMP_ERROR double fstrcmp(const char *string1, const char *string2); DESCRIPTION
The fstrcmp() function compares the two strings, string1 and string2. RETURN VALUE
The fstrcmp function returns a floating point value between 0.0 and FSTRCMP_IDENTICAL. A value of 0.0 means the strings are utterly un- alike. A value of FSTRCMP_IDENTICAL means the strings are identical. A value of more than FSTRCMP_THRESHOLD (it lies between 0.0 and FSTRCMP_IDENTICAL) would be considered "similar" by most people. A value of FSTRCMP_ERROR (always negative) indicates a malloc(3) failure. SEE ALSO
fmemcmp(3) fuzzy comparison of two memory areas fstrcasecmp(3) fuzzy comparison of two strings ignoring case fstrcmpi(3) fuzzy comparison of two strings strcmp(3) compare two strings COPYRIGHT
fstrcmp version 0.4 Copyright (C) 2009 Peter Miller Peter Miller <pmiller@opensource.org.au> The comparison code is derived from the fuzzy comparison functions in GNU Gettext 0.17. The GNU Gettext comparison functions were, in turn, derived from GNU Diff 2.7. Copyright (C) 1988-2009 Free Software Foundation fstrcmp(3)
All times are GMT -4. The time now is 07:38 PM.
Unix & Linux Forums Content Copyright 1993-2022. All Rights Reserved.
Privacy Policy