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# 1  
Old 05-02-2013
Help with FOR loop
Hello All,

I am trying to develop a script which invokes another script multiple times with different arguments passed to it. The invoked script accepts two arguments at a time. I created an argument file with all the arguments as below,

Code:
january february
march april
may june
july august

I developed the following script to execute my logic,

Code:
SCRPT="/home/ram/start_scrpt.sh"
        for i in `cat arguments`
        do
            $SCRPT $i
            if [ $? -ne 0 ]
            then
                  echo "Failure at $i" >> failure.log
            fi
        done

When I tried to execute the above code, the for loop is fetching as below,

Code:
january
february
march
april
may
june
july 
august

I require the for loop to pass the entire line one at a time from argument file as below

Code:
january february
march april
may june
july august



Please help..!!
Last edited by jim mcnamara; 05-02-2013 at 11:27 PM..
# 2  
Old 05-02-2013
Code:
SCRPT="/home/ram/start_scrpt.sh"
        while read i
        do
            $SCRPT $i
            if [ $? -ne 0 ]
            then
                  echo "Failure at $i" >> failure.log
            fi
        done < arguments

Reason: the for i in loop construct reads each WORD not each line.
This User Gave Thanks to jim mcnamara For This Post:
sravicha
# 3  
Old 05-02-2013
Thank you Jim. It works Smilie

---------- Post updated at 08:23 AM ---------- Previous update was at 08:05 AM ----------

Hello Jim,

I'm just wondering why the for loop didn't work as expected. If I am not wrong, it needs to fetch the whole line similar to the working of while loop. But why is it behaving otherwise?
# 4  
Old 05-03-2013
For loop wont fetch whole line it fetch till it find blank space in your case its after January.
# 5  
Old 05-03-2013
Quote:
Originally Posted by vidyadhar85
For loop wont fetch whole line it fetch till it find blank space in your case its after January.
To be more precise, the for loop does not care about that, it is the unquoted command substitution `cat arguments` together with the value of IFS that leads to fields being split in this fashion.
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