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UNIX for Dummies Questions & Answers

comparing 2 string variables in unix

 
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# 1  
Old 07-23-2008
Error comparing 2 string variables in unix
search=Jul 22
date=Jul 22

if [ "$search" = "$date" ]
then
echo They match

>>this piece of code does not detect that search and date are equivalent strings.. what's wrong with it?
# 2  
Old 07-23-2008
You can't assign values with spaces in them unless you quote them.

Code:
search="Jul 22"
date="Jul 22"

case $search in "$date") echo they match;; esac

The use of case is just to demonstrate a different approach; for simple equivalence (and with proper quoting) if [ ... ] is fine.
# 3  
Old 07-23-2008
Please use [ code ] and [ /code ] tags, ty Smilie

Code:
search="Jul 22"
date="Jul 22"

if [[ "$search" = "$date" ]]
then
echo They match

You should enclose the value of the variables with double quotes too, like you did inside the test. It is always good to check the current value of variables with a simple "echo".
The double squared brackets are optional but recommended.
# 4  
Old 07-23-2008
Oh, god morgon to Sweden btw! Smilie
# 5  
Old 07-23-2008
what if the string for the variable search will come from the output of a command line? placing-double-quotes solution will not be applicable then...
# 6  
Old 07-23-2008
How do you mean, as a parameter? Usually double quotes should still be ok... Best explain a bit further please, ty.
# 7  
Old 07-23-2008
Code:
search="$@"


date_files="`date -r "$i""

substring="${date_files:3:7}"

if [[ "$substring" = "$search" ]]

here's some parts of the code i'm working on..
this is how i initialized the string variables that i'm having problems with..
i already placed double quotes on the equations that will be initialized to the variables.. it still doesn't work.
 
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