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bash script help needed

Hi everyone, This is the first time I posting question here. Please be nice to me. I'm not a very experience Linux user so I really need some help here because of my limited knowledge to Linux.

I want to write a script to change few setting in few configuration files in RHEL 6 and 7. Below are some of the thing i want to archive:

1. Make a copy for all the files that will be modify by the script with format file.DDMMYYYY. If found a backup exist then ignore. Cause I done some testing and found out that if the scripts executed more than once in the same date, then the backup file will be the one that have made changes of.
2. The script will find certain parameter in a file and change the value if found. If not found then add the parameter in.
3. If the file is not found, then create the file and put the parameters in the file. Set permission for it as well.

Below is the noob script I have done, I know there are a lot of improvement with the script. The script is just an example of what needed to archive. Hope there will be nice guys willing to share their knowledge with me. :)

Code:

#!/bin/bash



###backup file###Please guide me how to ignore if the backup file already exist.###

cp -Rp /home/admin/Documents/1_file /home/admin/Documents/1_file.$(date +"%d%h%Y")

cp -Rp /home/admin/Documents/CIS.conf /home/admin/Documents/CIS.conf.$(date +"%d%h%Y")

cp -Rp /home/admin/Documents/2_file.conf /home/admin/Documents/2_file.conf.$(date +"%d%h%Y")



###Add line to the file###

echo "i successful add line to the file" > /home/admin/Documents/1_file



###Append line to the file###

echo "find and replace=not success" >> /home/admin/Documents/1_file



###Find word and replace###

sed -i 's/i successful add line to the file/admin successful add line to the file/' /home/admin/Documents/1_file



###Find line and replace###Problem facing here is the "=" might have space or non space, how do i find the setting and replace whatever after with a value?###

sed -i 's/find and replace=not success/find and replace=success/' /home/admin/Documents/1_file



###Create file and add text to it###How to check if the file not exist, then only create?###

touch notfound.conf

cat<<END>notfound.conf

Line1

Line2

Line3

Line4

Line5

END





###Find parameter in a file and replace the value###

sed -i "s/Line4/Line5/" notfound.conf

sed -i "s/Line2/Line4/" notfound.conf



###Change permission and owner###

chmod 644 notfound.conf

chown admin:admin notfound.conf



###Find parameter with hashtag and unhastag them/vice versa, change the value also###Same issue with previous one, the output is the word will be insert in between which have two = ####

sed -i "r/#Try unhashtag me*/Try unhashtag me = success/" /home/admin/Documents/2_file.conf

sed -i 's/Try hashtag/#Try hashtag* = sucess/' /home/admin/Documents/2_file.conf

Quote:

Originally Posted by OnionBoy (Post 5970749)

###backup file###Please guide me how to ignore if the backup file already exist.###

Here is an example for how to check if file exists: https://stackoverflow.com/questions/...-exist-in-bash

Also, if you use code tags, it is lot easier to read...

Quote:

Originally Posted by dc.901 (Post 5970754)

Here is an example for how to check if file exists: https://stackoverflow.com/questions/...-exist-in-bash

Also, if you use code tags, it is lot easier to read...

Thanks, will try the code tags next time.

Quote:

Originally Posted by dc.901 (Post 5970754)

Here is an example for how to check if file exists: https://stackoverflow.com/questions/...-exist-in-bash

Also, if you use code tags, it is lot easier to read...

Really thanks for the guide...So I tested with the recommended step:

Code:

#!/bin/bash

if [ ! -e /home/admin/Documents/new.conf ]; then

echo 'create new.conf'

touch new.conf

cat<<END>> new.conf

Setting_A=A

Setting_B=2

Setting_C=F

Setting_D = 0

END

        else

if [ ! -e /home/admin/Documents/new.conf.$(date +"%d%h%Y") ]; then

cp -Rp /home/admin/Documents/new.conf /home/admin/Documents/new_conf.$(date +"%d%h%Y")

sed -i 's/Setting_C=*/Setting_C=C/' /home/admin/Documents/new.conf

sed -i 's/Setting_D*/Seeting_D=4/' /home/admin/Documents/new.conf

fi

fi

The problem i have is with the changes on the text inside file....the output i getting is below if I execute more than once:

Quote:

root@ubuntu00:/home/admin/Documents# cat new.conf
Seeting_D=4A=A
Seeting_D=4B=2
Seeting_D=4C=CF
Seeting_D=4 = 0

anyone can help on that part....

You need a leading '.' when using globs with sed.

Consider this example.

Code:

$ foo='Setting_C=foo'

$ echo $foo | sed 's/Setting_C=*/Setting_C=C/'

Setting_C=Cfoo

$ echo $foo | sed 's/Setting_C=.*/Setting_C=C/'

Setting_C=C

your two timing cat fix.

Code:

#!/bin/bash



cat<<END> new.conf

Setting_A=A

Setting_B=2

Setting_C=F

Setting_D = 0

END



cat ~/new.conf



[[ ~/new.conf ]] && \

{ sed -i 's#.*Setting_D.*#Setting_D=4#' ~/new.conf  ; }



cat ~/new.conf

You can drop the back slashes after '&&' or '||'. :)