Sponsored Content
Top Forums Shell Programming and Scripting problem in string comparison in shell programming Post 302292095 by fpmurphy on Friday 27th of February 2009 12:12:33 AM
Old 02-27-2009
Quote:
It should work for any values. It compares "lexicographically in the current locale".
Not necessarily true. It will result in an unsatisfactory ordering for certain locales unless the correct collator (for the locale) is provided in the underlying OS to allow locale-sensitive ordering. Bash and other shells do not include built-in collators.

Some shells such as ksh93 and zsh specifically avoid the issue for this reason. From the ksh93 man page
Quote:
string1 < string2
True, if string1 comes before string2 based on ASCII value of their characters.
string1 > string2
True, if string1 comes after string2 based on ASCII value of their characters.
The zsh manual has almost identical text.
 

10 More Discussions You Might Find Interesting

1. Programming

Unix Programming Book Comparison

Hi, I am starting out to program on Unix, having had experience in C and C++ in DOS. I would like to know, of these three, which is the best book for learning C programming in Unix: Advanced Unix Programming by Marc Rochkind Advanced Unix Programming by Warren Gay Advanced Programming in... (6 Replies)
Discussion started by: theicarusagenda
6 Replies

2. Shell Programming and Scripting

Problem in ksh script ( String comparison )

hi , i am trying to compre two strings if ] or if ] when the length of var1 is small (around 300-400 char ) it works fine but when it is large (around 900-1000 chars) it fails is there any limitations for this type of comparison ??? (3 Replies)
Discussion started by: amarnath
3 Replies

3. AIX

Problem in ksh script ( String comparison )

hi , i am trying to compre two strings if ] or if ] when the length of var1 is small (around 300-400 char ) it works fine but when it is large (around 900-1000 chars) it fails is there any limitations for this type of comparison ??? (1 Reply)
Discussion started by: amarnath
1 Replies

4. Shell Programming and Scripting

bash shell script string comparison

I want to remove a line that has empty string at second field when I use cut with delimeter , like below $cat demo hello, mum hello, #!/bin/sh while read line do if then # remove the current line command goes here fi done < "demo" i got an error message for above... (4 Replies)
Discussion started by: bonosungho
4 Replies

5. Solaris

String Comparison in Shell script

I Have a script which gets the status of oracle database and if the status is READ WRITE ..it should echo "db is up " else "db is down" Here is the code if then echo "db up" else echo "db down" fi done; The script is giving me out put "db down" even thoug the value of... (6 Replies)
Discussion started by: njafri
6 Replies

6. Shell Programming and Scripting

Arithmetic Problem with shell script programming.

Hello everybody, I decided to take a Unix Introduction class and have never had experience with programming. Everything was fine until recently when the Prof. started shell scripting and he wants us to make a small script to add unlimited numbers from arguments and from standard input. I... (1 Reply)
Discussion started by: Florinel76
1 Replies

7. Homework & Coursework Questions

Arithmetic Problem with shell script programming.

Hello everybody, I decided to take a Unix Introduction class and have never had experience with programming. Everything was fine until recently when the Prof. started shell scripting and he wants us to make a small script to add unlimited numbers from arguments and from standard input. I... (8 Replies)
Discussion started by: Florinel76
8 Replies

8. Shell Programming and Scripting

String comparison problem

Hi, can someone please help me!!! urgent! I have a strange issue here. I grep for 2 strings from a txt files and compare the string value. Though the string values are the same, they are compared as different values. Please help Case-1 -------- Here I grep for 2 different field values... (3 Replies)
Discussion started by: vani123
3 Replies

9. Shell Programming and Scripting

Problem in string comparison

guys , i am using inotify for monitoring one directory to check core file generation , my snippet of code is follows #!/bin/bash DIR=$1 inotifywait -q -e create -m $DIR | while read path events name; do if ]; then echo "Now I am going to do something with $name in directory $path."... (5 Replies)
Discussion started by: baker
5 Replies

10. Shell Programming and Scripting

awk string comparison unterminated quoted string andrule of thumb

I have the logic below to look up for matches within the columns between the two files with awk. In the if statement is where the string comparison is attempted with == The issue seems to be with the operands, as 1. when " '${SECTOR}' " -- double quote followed by single quote -- awk matches... (1 Reply)
Discussion started by: deadyetagain
1 Replies
tr(1)							      General Commands Manual							     tr(1)

NAME
tr - translate characters SYNOPSIS
string1 string2 string1 string1 string1 string1 DESCRIPTION
copies the standard input to the standard output with substitution or deletion of selected characters. Input characters from string1 are replaced with the corresponding characters in string2. If necessary, string1 and string2 can be quoted to avoid pattern matching by the shell. recognizes the following command line options: Translates on a byte-by-byte basis. When this flag is specified does not support extended characters. Complements the set of characters in string1, which is the set of all characters in the current character set, as defined by the current setting of except for those actually specified in the string1 argument. These characters are placed in the array in ascending collation sequence, as defined by the current setting of Deletes all occurrences of input characters or collating elements found in the array specified in string1. If and are both specified, all characters except those specified by string1 are deleted. The contents of string2 are ignored, unless is also specified. Note, however, that the same string cannot be used for both the and the flags; when both flags are specified, both string1 (used for deletion) and string2 (used for squeezing) are required. If is not specified, each input character or collating element found in the array specified by string1 is replaced by the character or collating element in the same relative position specified by string2. Replaces any character specified in string1 that occurs as a string of two or more repeating characters as a single instance of the character in string2. If the string2 contains a character class, the argument's array contains all of the characters in that character class. For example: In a case conversion, however, the string2 array contains only those characters defined as the second characters in each of the or character pairs, as appropriate. For example: The following abbreviation conventions can be used to introduce ranges of characters, repeated characters or single-character collating elements into the strings: c1-c2 or Stands for the range of collating elements c1 through c2, inclusive, as defined by the current setting of the locale category. Stands for all the characters belonging to the defined character class, as defined by the current setting of locale category. The following character class names will be accepted when spec- ified in string1: or Character classes are expanded in collation order. When the and flags are specified together, any of the character class names are accepted in string2; otherwise, only character class names or are accepted in string2 and then only if the corresponding character class and respectively) is specified in the same relative position in string1. Such a specification is interpreted as a request for case conversion. When appears in string1 and appears in string2, the arrays contain the characters from the mapping in the category of the current locale. When appears in string1 and appears in string2, the arrays contain the characters from the map- ping in the category of the current locale. Stands for all the characters or collating elements belonging to the same equivalence class as c, as defined by the current setting of locale category. An equivalence class expression is allowed only in string1, or in string2 when it is being used by the combined and options. Stands for n repetitions of a. If the first digit of n is n is considered octal; otherwise, n is treated as a decimal value. A zero or missing n is interpreted as large enough to extend string2-based sequence to the length of the string1-based sequence. The escape character can be used as in the shell to remove special meaning from any character in a string. In addition, followed by 1, 2, or 3 octal digits represents the character whose ASCII code is given by those digits. An ASCII NULL character in string1 or string2 can be represented only as an escaped character; i.e. as but is treated like other characters and translated correctly if so specified. NULL characters in the input are not stripped out unless the option is given. EXTERNAL INFLUENCES
Environment Variables provides a default value for the internationalization variables that are unset or null. If is unset or null, the default value of "C" (see lang(5)) is used. If any of the internationalization variables contains an invalid setting, will behave as if all internationalization variables are set to "C". See environ(5). If set to a non-empty string value, overrides the values of all the other internationalization variables. determines the interpretation of text as single and/or multi-byte characters, the classification of characters as printable, and the char- acters matched by character class expressions in regular expressions. determines the locale that should be used to affect the format and contents of diagnostic messages written to standard error and informa- tive messages written to standard output. determines the location of message catalogues for the processing of RETURN VALUE
exits with one of the following values: All input was processed successfully. An error occurred. EXAMPLES
For the ASCII character set and default collation sequence, create a list of all the words in file1, one per line in file2, where a word is taken to be a maximal string of alphabetics. Quote the strings to protect the special characters from interpretation by the shell (012 is the ASCII code for a new-line (line feed) character): Same as above, but for all character sets and collation sequences: Translate all lower case characters in file1 to upper case and write the result to standard output. Use an equivalence class to identify accented variants of the base character in file1, strip them of diacritical marks and write the result to file2: Translate each digit in file1 to a (number sign), and write the result to file2. The (asterisk) tells to repeat the (number sign) enough times to make the second string as long as the first one. AUTHOR
was developed by OSF and HP. SEE ALSO
ed(1), sh(1), ascii(5), environ(5), lang(5), regexp(5). STANDARDS CONFORMANCE
tr(1)
All times are GMT -4. The time now is 09:44 AM.
Unix & Linux Forums Content Copyright 1993-2022. All Rights Reserved.
Privacy Policy