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Writing if condition in shell script and failing to do requirement

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# 1  
Old 04-23-2014
Writing if condition in shell script and failing to do requirement
Hi,

I am trying to edit the values in a file. For example i am trying to edit the value of "ABC" in a file by executing shell script.

Please Note that ABC value can be there mulitple times or it may not be there in the file
Conditions for it is

1. If ABC is less than 123 then it should change the ABC value to 123
2. If ABC is greater than 123 then it should leave the ABC value to existing value only as it is greater than 123
3. If ABC is not there is file then it should add ABC=123 in file.

Code i am trying is not working. PFB

Code:

     if [ $ABC -lt 123 ]
     then
        sed -i "s|\("ABC" *= *\).*|\1123|" file.con
     fi

    if [ $ABC -gt 123 ]
     then

    "ABC=$ABC" >> file.con  

     else

     echo "kernel.shmall=" >> /mqseries1/sysctl.conf
     sed -i "s|\("kernel.shmall" *= *\).*|\1123|" file.con
     
     fi

Experts can you please help me over here?
# 2  
Old 04-23-2014
Also, provide the contents of file.con
# 3  
Old 04-23-2014
Content is

Code:
########################

ABC=342
#XYZ=892


CR=5678
ABC=23
XYZ=1892

ABC=2654

Last edited by darling; 04-23-2014 at 12:15 PM..
# 4  
Old 04-23-2014
here you go

Code:
       flag=0
       for file in $(cat con);
        do
                field=`echo $file | awk 'BEGIN { FS = "=" } { print $1 }'`
                val=`echo $file | awk 'BEGIN { FS = "=" } { print $2 }'`
                        if [ $field = "ABC" ] && [ $val -gt 123 ]; then
                               echo $field"="$val >> con2
                               flag=1
                        elif [ $field = "ABC" ] && [ $val -lt 123 ]; then
                                echo $field"=123" >> con2
                                flag=1
                        elif [ $field != "ABC" ]; then
                                echo $field"="$val >> con2
                        fi
        done

                        if [ $flag -eq 0 ]; then
                                echo "ABC=123" >> con2
                        fi

---------- Post updated at 10:45 AM ---------- Previous update was at 10:41 AM ----------

contents of con file

Code:
ABC=342
#XYZ=892


CR=5678
ABC=23
XYZ=1892

ABC=2654

---------- Post updated at 10:47 AM ---------- Previous update was at 10:45 AM ----------

contents of con2 after executing script

Code:
ABC=342
#XYZ=892
CR=5678
ABC=123
XYZ=1892
ABC=2654

# 5  
Old 04-23-2014
When i executed the script 3 times, i got output as below. Output is adding to exisiting one. but ideally it should alter the existing one.
Code:
ABC=342
#XYZ=892
CR=5678
ABC=123
XYZ=1892
ABC=2654
ABC=342
#XYZ=892
CR=5678
ABC=123
XYZ=1892
ABC=2654
ABC=342
#XYZ=892
CR=5678
ABC=123
XYZ=1892
ABC=2654

# 6  
Old 04-24-2014
You didn't show us how the shell variable ABC was set in your script and there was no mention of updating kernel.shmall so I don't know what this code from your script is trying to do:
Code:
     echo "kernel.shmall=" >> /mqseries1/sysctl.conf
     sed -i "s|\("kernel.shmall" *= *\).*|\1123|" file.con

Other than that, you could try something like:
Code:
#!/bin/ksh
file=${1:-file.con}
cp "$file" "_$file" && awk '
BEGIN {	FS = OFS = "=" }
$1 == "ABC" {
	found++
	if($2 < 123) $2 = 123
}
1
END {	if(!found) print "ABC=123" }
' "_$file" > "$file"

Unlike your script, this will leave a backup of your input file using the input filename with a leading underscore as the backup file. Although tested with a Korn shell, this will work with any shell that recognizes POSIX shell variable expansions.

By default, this script works on a file named file.con (as in your example), but you can invoke this script with one operand that names any file you want it to process.
# 7  
Old 04-24-2014
Code:
       flag=0
       for file in $(cat con);
        do
                field=`echo $file | awk 'BEGIN { FS = "=" } { print $1 }'`
                val=`echo $file | awk 'BEGIN { FS = "=" } { print $2 }'`
                        if [ $field = "ABC" ] && [ $val -ge 123 ]; then
                               echo $field"="$val >> con2
                               flag=1
                        elif [ $field = "ABC" ] && [ $val -lt 123 ]; then
                                echo $field"=123" >> con2
                                flag=1
                        elif [ $field != "ABC" ]; then
                                echo $field"="$val >> con2
                        fi
        done

                        if [ $flag -eq 0 ]; then
                                echo "ABC=123" >> con2
                        fi
                cat con2 > con
                rm con2
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