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problem in string comparison in shell programming


 
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# 1  
problem in string comparison in shell programming

Hello,
was just wondering how to compare strings in unix? I mean as in C there is a function strcmp() in string.h, is there any function in unix for that? I tried using
Code:
    if [ "p" > "q" ]

and all such variations but didn't succeed. Any help would be appreciated. Thanks in advance Smilie
# 2  
CPU & Memory

Hi,

you can compare string..like below..

if [ $valuea -ge $valueb ]
then
command
else
command
fi

to compare two strings..

you can use lessthan --> -le
greater than -ge
equal -eq

Thanks
Sha
# 3  
solution

hi
you can compare the string by the following commands as u have told strcmp() in C
if [ "$string1" == "$string2" ]
then

else


fi
# 4  
Quote:
Originally Posted by salman4u
was just wondering how to compare strings in unix? I mean as in C there is a function strcmp() in string.h, is there any function in unix for that? I tried using
Code:
    if [ "p" > "q" ]

and all such variations but didn't succeed. Any help would be appreciated. Thanks in advance Smilie

In bash, you can compare alphabetically, but it is not standard. You need to escape the angle bracket:

Code:
if [ p \> q ]

# 5  
Quote:
Originally Posted by Shahul
Hi,

you can compare string..like below..

if [ $valuea -ge $valueb ]
then
command
else
command
fi

to compare two strings..

you can use lessthan --> -le
greater than -ge
equal -eq

Thanks
Sha
I dont think you can compare strings with -le -gt -ge. It's meant for only integer comparison.
# 6  
Quote:
Originally Posted by cfajohnson

In bash, you can compare alphabetically, but it is not standard. You need to escape the angle bracket:

Code:
if [ p \> q ]

cfajohnson Smilie You're the man. Thanks!!
# 7  
Just a quick note - the string comparison is based on the ASCII value of the characters in the string and may fail for strings containing non-ASCII characters.

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