Shell Programming and Scripting

Hi Guys,

i'm trying to use sed to replace the second occurrence of the 3 digit number in an I.P address and replace it with another value but it errors out. please advise

Code:

$ cat infil
3538,,,,,,ID,ID1,,,,,,,,,,,123.110.24.5

Code:

sed 's/[0-9]\{1,3\}\./x\./\2/' infil
sed: -e expression #1, char 22: unknown option to `s'

same error when i use with -e switch . can some point me where i'm going wrong here

sed's substitute command's format: s/re/repl/flags
Note the absence of a trailing forward-slash delimiter. You want to use a flag value of 2, not \2/.

Although it probably has nothing to do with the error, the dot is not special in the replacement text. You can simply write x. instead of x\.. Pedantically speaking, \. in the replacement text is an undefined sequence. An implementation is allowed to treat it as it pleases; it can treat the backslash specially and quote the dot, or it can treat the backslash literally and replace the matching text with \., or it can abort with a syntax error. Dropping the backslash in the replacement text is the simplest and most portable option.

Regards,
Alister

thanks allister. as you pointed out i had 2 issues in there . one was with the extra \ after the replace pattern and the extra \ before the flag of 2nd occurrence. that fixed it .

also, the treatment of \ before the dot was not necessary in this case.

Thanks mate.