Shell Programming and Scripting

\s is not valid in posix-compliant posix (perhaps it's a gnu sed extension, but I'm not sure). Even if it's allowed, that regular expression would only match a line with one matching character. And, since sed prints all lines by default, the p command in this case will cause matching lines to print twice.

Two portable sed alternatives:

Code:

sed -n '/^[[:alnum:][:blank:].-]*$/p' file1
sed '/^[[:alnum:][:blank:].-]*$/!d' file1

The first disabled printing by default, with the -n option, and then only prints lines that consist of nothing but the allowed characters. The second option deletes all lines that do not consist of all matching characters.

Regards,
Alister

---------- Post updated at 11:56 AM ---------- Previous update was at 11:53 AM ----------

I've been having vision troubles the past few days. Seconds after posting, I noticed anbu's post. Mine is essentially the same, except it uses character classes.

Thanks a lot anbu23 and Alister, it was very helpful. I have a doubt. how can i do this task for a particular part of the line..for example, i want to check for the special characters in all lines from position 10 to 20 only..

Code:

$ cat file
691775025 ýÄqJ8^Z^Y{ 2004-08-23E P 100.00
45585025 0527541139295037342008-07-25OEP 100.00
6983025 ýB<9D>x<^F^Xb 2004-11-16SPP 100.00
$ awk ' !gsub("[^-.0-9A-Za-z ]","",substr($0,10,10)) ' file
45585025 0527541139295037342008-07-25OEP 100.00