Executing String value as a command

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May 10th, 2012, 01:22 PM

sujoydc

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Join Date: May 2012

Posts: 14

Time spent in forums: 6 h 41 m
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Executing String value as a command

Hello Linux Gurus,
I have a typical requirement:
1. I have a file where I kept all the commands in each line like key=value
eg.

Properties file entry Code:

Original - Properties file entry Code
check_java_command=`ls -ld /app/java/jdk160_20-linux64bit \| awk '{print $8}'` check_java_value="/app/java/jdk160_20-linux64bit" check_jrockit_command="ls -ld /app/java/jrockit28jdk160_20-64b \| awk '{print $8}'" check_jrockit_value="/app/java/jrockit28jdk160_20-64b"


check_java_command=`ls -ld /app/java/jdk160_20-linux64bit | awk '{print $8}'`
check_java_value="/app/java/jdk160_20-linux64bit"

check_jrockit_command="ls -ld /app/java/jrockit28jdk160_20-64b | awk '{print $8}'"
check_jrockit_value="/app/java/jrockit28jdk160_20-64b"

2. Then I loop through this file like below:

Code:

grep '_command' command.properties | awk -F= '{print $1}' | while read command; do
echo "Command:"$command
                if [[ "$command" != \#* ]] ; then
                        KEY=${command%_command}
                        echo "Key is:"$KEY
                        COMMAND=`grep '^'"$KEY"'_command' command.properties | awk -F= '{print $2}'`
                        VALUE=`grep '^'"$KEY"'_value' command.properties | awk -F= '{print $2}'`
                        echo "Command="$COMMAND
                        echo "Value="$VALUE
                        COMMAND=eval ${COMMAND}
                        echo "Executed Command  :"$COMMAND
                        if [[ "$COMMAND" == "$VALUE" ]]; then
                                echo $KEY executed successfully...
                                
                        else
                                echo $KEY execution failed...
                                
                        fi
                else
                        echo "This is a comment!"
                fi
             done

3. Now the command is getting read from the file nicely but I can't execute that command. I tried using eval/$/another ``/" " sign and what not.

I don't have fundamental knowledge so please guide me what's wrong here and how can I fix it?

Thanks,

May 11th, 2012, 07:44 AM

sujoydc

Registered User

Join Date: May 2012

Posts: 14

Time spent in forums: 6 h 41 m
Reputation Power: 0

I would appreciate if someone can shed some light on this.
Is this something can't be done? or doable somehow.

Quote:

Originally Posted by sujoydc

Hello Linux Gurus,
I have a typical requirement:
1. I have a file where I kept all the commands in each line like key=value
eg.

Properties file entry Code:

Original - Properties file entry Code
check_java_command=`ls -ld /app/java/jdk160_20-linux64bit \| awk '{print $8}'` check_java_value="/app/java/jdk160_20-linux64bit" check_jrockit_command="ls -ld /app/java/jrockit28jdk160_20-64b \| awk '{print $8}'" check_jrockit_value="/app/java/jrockit28jdk160_20-64b"


check_java_command=`ls -ld /app/java/jdk160_20-linux64bit | awk '{print $8}'`
check_java_value="/app/java/jdk160_20-linux64bit"

check_jrockit_command="ls -ld /app/java/jrockit28jdk160_20-64b | awk '{print $8}'"
check_jrockit_value="/app/java/jrockit28jdk160_20-64b"

2. Then I loop through this file like below:

Code:

grep '_command' command.properties | awk -F= '{print $1}' | while read command; do
echo "Command:"$command
                if [[ "$command" != \#* ]] ; then
                        KEY=${command%_command}
                        echo "Key is:"$KEY
                        COMMAND=`grep '^'"$KEY"'_command' command.properties | awk -F= '{print $2}'`
                        VALUE=`grep '^'"$KEY"'_value' command.properties | awk -F= '{print $2}'`
                        echo "Command="$COMMAND
                        echo "Value="$VALUE
                        COMMAND=eval ${COMMAND}
                        echo "Executed Command  :"$COMMAND
                        if [[ "$COMMAND" == "$VALUE" ]]; then
                                echo $KEY executed successfully...
                                
                        else
                                echo $KEY execution failed...
                                
                        fi
                else
                        echo "This is a comment!"
                fi
             done

May 11th, 2012, 10:02 AM

sujoydc

Registered User

Join Date: May 2012

Posts: 14

Time spent in forums: 6 h 41 m
Reputation Power: 0

Found the answer:

`eval "$COMMAND"`

Quote:

Originally Posted by sujoydc

I would appreciate if someone can shed some light on this.
Is this something can't be done? or doable somehow.

May 11th, 2012, 10:11 AM

SimonJM

Contributing User

Join Date: Mar 2006

Posts: 2,108

Time spent in forums: 1 Month 1 Week 1 Day 4 h 41 m
Reputation Power: 1485

It's a horrible way of doing it, are all the things in that file the same format? If so there's are far nicer ways of doing this. You seem to have two related lines for each item, and use those to determine if that item (a file name) exists. If all you had was the filename then all you'd need to do woudl be to loop over the contents and have the actual commands explicitly in your script:

Code:

for file in $(grep -v "^#" /path/to/config.file)
do
  if [ -f $file ]
  then
    echo "exists"
  else
    echo "not exists"
  fi
done

__________________
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The moon on my left and the dawn on my right.
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May 15th, 2012, 10:02 AM

sujoydc

Registered User

Join Date: May 2012

Posts: 14

Time spent in forums: 6 h 41 m
Reputation Power: 0

Hi Simon,
Thanks for your reply.
I not only have folders to check, I can have any type of unix commands there. So, that's why i can't always check -f.

Thanks,
~Sujoy

Executing String value as a command

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