Read a file and comment a line with matching a string via shell script
I want to comment a matching line of file (final_ip) via shell script
I have a input file (input_ip) if the searching ip is matching on final_ip file, change the file content mentioned below
Before changing :
192.168.1.12 #SAM
After the change, the matching line must be replacing :
# 192.168.1.12 #SAM
sed '/<string>/s/^/<comment_char>/' <file>
/<string>/ operates on the lines matching <string>. ^ operates on the beginning of the line and inserts the comment character.
As I understand you you want to read the IP address from a file. Then you can use the following script. Usage: script <file_containing_the_IP_address> <file_to_operate_on>
#!/bin/sh
ip_file="$1"
file_to_change="$2"
comment='# '
ip=$(sed 's/\./\\./g' "$ip_file")
temp_file=$(mktemp)
sed "/$ip/s/^/$comment/" "$file_to_change" > "$temp_file" &&
mv -- "$temp_file" "$file_to_change"
exit 0
If the script doesn't need to be portable you can also use GNU sed's -i switch.
This uses GNU sed's -i extension to edit the final_ip file in-place:
input=`cat input_ip`
sed -i "s/$input/# $input/" final_ip
Putting double-quotes around sed's script allows for the $input variable to be interpolated. Only works if there's one IP in the input_ip file.
