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find and replace query

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# 1  
Old 05-26-2009
find and replace query
Hello ppl,

I am writing a script which finds multiple words match and replace it with new words.
I have server.conf file which looks like
Code:
### Welcome to server ###
### Server address and port ###
 
Server=127.0.0.1 
### Replace Server=0.0.0.0 ###
 
ServerPort=0
### Replace ServerPort=1 ####
### Enable Server ##
 
Enable Server=1
 
### Replace Enable Server=0 ###
### END OF FILE ##

-----------------------------------------------------------
i have written code for it as shown below
Code:
FILE="/opt/server.conf"
NEW_FILE="/opt/new_server.conf"
        
 IFS=""
        for line in `cat ${FILE}`; do
        #echo ${line}
        if [ -n "`echo ${line} | grep 'Server=127.0.0.1'`" ]
        then
                 echo ${line} | sed 's|Server=127.0.0.1|Server=0.0.0.0|g' >>$NEW_FILE
        elif [ -n "`echo ${line} | grep 'ServerPort=0'`" ]
        then
                echo ${line} | sed 's|ServerPort=0|ServerPort=1|g' >>$NEW_FILE
        elif [ -n "`echo ${line} | grep 'Enable Server=1'`" ]
        then
                echo ${line} | sed 's|Enable Server=1|Enable Server=0|g' >>$NEW_FILE
        else
                echo ${line} >>$NEW_FILE
        fi
        done

But when I run my script it only replaces the first match (Server=0.0.0.0). Remaining two matches doesnt change.
I don’t know what wrong with my code.

Can anyone help me on this?
Thanks in advance
Last edited by lightdensity; 05-26-2009 at 01:14 PM..
# 2  
Old 05-26-2009
Code:
sed '/Server=127.0.0.1/{s//Server=0.0.0.0/g}
/ServerPort=0/{s//ServerPort=1/g}
/Enable Server=1/{s//Enable Server=0/g}
' /opt/server.conf > /opt/new_server.conf

-Devaraj Takhellambam
# 3  
Old 05-26-2009
Quote:
Originally Posted by devtakh
Code:
sed '/Server=127.0.0.1/{s//Server=0.0.0.0/g}
/ServerPort=0/{s//ServerPort=1/g}
/Enable Server=1/{s//Enable Server=0/g}
' /opt/server.conf > /opt/new_server.conf

-Devaraj Takhellambam
thanks for your response..Actually i am new to shell scripting
Code:
FILE="/opt/server.conf"
NEW_FILE="/opt/new_server.conf"
        
 IFS=""
        for line in `cat ${FILE}`; do
        #echo ${line}
        if [ -n "`echo ${line} | grep 'Server=127.0.0.1'`" ]  #grep command searches for right string
        then
                 echo ${line} | sed 's|Server=127.0.0.1|Server=0.0.0.0|g' >>$NEW_FILE
        elif [ -n "`echo ${line} | grep 'ServerPort=0'`" ]
        then
                echo ${line} | sed 's|ServerPort=0|ServerPort=1|g' >>$NEW_FILE
        elif [ -n "`echo ${line} | grep 'Enable Server=1'`" ]
        then
                echo ${line} | sed 's|Enable Server=1|Enable Server=0|g' >>$NEW_FILE
        else
                echo ${line} >>$NEW_FILE
        fi
        done

So, how to find out which for the right string??

thanks
# 4  
Old 05-26-2009
Your IFS is set wrong. THe IFS="" says there is no separator so the whole file is read. You can only use IFS is there is actually a seperator between each field. So cat $FILE will not give you line by line it will give you the while file as a field at once. Hence only matching 1 time. Since you really want look at each line as a record you should use awk or sed to find and replace the text.

So this will work for you which was posted by devtakh which says search the whole file and replace the matching pattern with the given pattern for each instance you want to change. It will find each one separately and change the file the way you want.

sed '/Server=127.0.0.1/{s//Server=0.0.0.0/g}
/ServerPort=0/{s//ServerPort=1/g}
/Enable Server=1/{s//Enable Server=0/g}
' /opt/server.conf > /opt/new_server.conf
# 5  
Old 05-26-2009
Quote:
Originally Posted by BubbaJoe
Your IFS is set wrong. THe IFS="" says there is no separator so the whole file is read. You can only use IFS is there is actually a seperator between each field. So cat $FILE will not give you line by line it will give you the while file as a field at once. Hence only matching 1 time. Since you really want look at each line as a record you should use awk or sed to find and replace the text.
thanks for help..

so what if i set
IFS="\n\t"

than i guess, cat $FILE will give line by line..

ok!! i will try it out.. meanwhile could you check my remaining code.. and tell whether my code is correct or not.

thanksSmilie
# 6  
Old 05-26-2009
Quote:
Originally Posted by lightdensity
thanks for your response..Actually i am new to shell scripting
Code:
FILE="/opt/server.conf"
NEW_FILE="/opt/new_server.conf"
        
 IFS=""
        for line in `cat ${FILE}`; do
        #echo ${line}
        if [ -n "`echo ${line} | grep 'Server=127.0.0.1'`" ]  #grep command searches for right string
        then
                 echo ${line} | sed 's|Server=127.0.0.1|Server=0.0.0.0|g' >>$NEW_FILE
        elif [ -n "`echo ${line} | grep 'ServerPort=0'`" ]
        then
                echo ${line} | sed 's|ServerPort=0|ServerPort=1|g' >>$NEW_FILE
        elif [ -n "`echo ${line} | grep 'Enable Server=1'`" ]
        then
                echo ${line} | sed 's|Enable Server=1|Enable Server=0|g' >>$NEW_FILE
        else
                echo ${line} >>$NEW_FILE
        fi
        done

So, how to find out which for the right string??

thanks
It will be a waste of resource to use the shell script when sed can handle it. you do not need to check if the word exists and if it exists, then replace it. sed can do that for you.
But incase you need to do..I suggest you use while loop, instead of a for loop with the cat command.

Code:
FILE="/opt/server.conf"
NEW_FILE="/opt/new_server.conf"
        
       while read line
   do
        #echo ${line}
        if [ -n "`echo ${line} | grep 'Server=127.0.0.1'`" ]  #grep command searches for right string
        then
                 echo ${line} | sed 's|Server=127.0.0.1|Server=0.0.0.0|g' >>$NEW_FILE
        elif [ -n "`echo ${line} | grep 'ServerPort=0'`" ]
        then
                echo ${line} | sed 's|ServerPort=0|ServerPort=1|g' >>$NEW_FILE
        elif [ -n "`echo ${line} | grep 'Enable Server=1'`" ]
        then
                echo ${line} | sed 's|Enable Server=1|Enable Server=0|g' >>$NEW_FILE
        else
                echo ${line} >>$NEW_FILE
        fi
        done < $FILE

-Devaraj Takhellambam
# 7  
Old 05-27-2009
if you have Python
Code:
#!/usr/bin/env python
import fileinput
d={ "Server":"0.0.0.0", "ServerPort":"1", "Enable Server":"0" }
for line in fileinput.FileInput("file",inplace=1):
    line=line.strip()
    if not line.startswith("#") and line!="":
        line=line.split("=")        
        print line[0]+"="+d[line[0]]
    else:
        print line

output
Code:
# ./test.py
# more file
### Welcome to server ###
### Server address and port ###

Server=0.0.0.0
### Replace Server=0.0.0.0 ###

ServerPort=1
### Replace ServerPort=1 ####
### Enable Server ##

Enable Server=0

### Replace Enable Server=0 ###
### END OF FILE ##
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