Visit Our UNIX and Linux User Community


GREP a string with NULL Character


 
Thread Tools Search this Thread
Top Forums UNIX for Dummies Questions & Answers GREP a string with NULL Character
# 1  
Old 09-13-2001
Question GREP a string with NULL Character

Does anyone know how to use grep/egrep to find a string that contains a null character?

i.e.: the string looks like this: null0001nullN

well I want to be able to : grep '0001N'

is there a wildcard character or something that I can put in the grep to include the nulls?
# 2  
Old 09-16-2001
Well, I've never actually tried this but the
ASCII control code for NUL is CTRL-@ (^@).
I'm not exactly sure how you could embed this
in a grep regular expression but you might be able
to use the CTRL-V method. By this I mean, if you
type CTRL-V, the next character is rendered as
a control character representation. However, I'm
not sure if this works with NUL. For instance,
you can type CTRL-V followed by "Enter" and you
should see ^M displayed.

Give it a shot.
# 3  
Old 09-18-2001
Still a no go

I gave it a shot, but missed the target.

Thanks for the suggestion!
# 4  
Old 09-18-2001
I tried everything but I couldn't get this to work. I'm pretty sure that the problem in the NULL character. To a c program, a string is terminated by a null and grep seems to be behaving that way. Maybe

grep 0001 | grep N

will help you a little.
 

Previous Thread | Next Thread
Test Your Knowledge in Computers #582
Difficulty: Medium
A buffered input or output stream is one in which data that is read or written is actually stored in memory in a buffer until such a time as the buffer is flushed and the accumulated data is passed to or from the actual file.
True or False?

10 More Discussions You Might Find Interesting

1. Shell Programming and Scripting

Remove first NULL Character in Flat File

We have a flat file with below data : ^@^@^@^@00000305^@^@^@^@^@^@430^@430^@^@^@^@^@^@^@^@^@09079989530As we can see ^@ is Null character in this file I want to remove only the first few null characters before string 00000305 How can we do that, any idea. I want a new file without first few... (5 Replies)
Discussion started by: simpltyansh
5 Replies

2. Shell Programming and Scripting

sed searches a character string for a specified delimiter character, and returns a leading or traili

Hi, Anyone can help using SED searches a character string for a specified delimiter character, and returns a leading or trailing space/blank. Text file : "1"|"ExternalClassDEA519CF5"|"Art1" "2"|"ExternalClass563EA516C"|"Art3" "3"|"ExternalClass305ED16B8"|"Art9" ... ... ... (2 Replies)
Discussion started by: fspalero
2 Replies

3. Shell Programming and Scripting

If grep value is null then assign 0 to variable

DELETE=`cat $logfile1 | egrep -i "Delete" | sed 's/ */ /g' | cut -d" " -f2` INSERT=`cat $logfile1 | egrep -i "Insert" | sed 's/ */ /g' | cut -d" " -f2` UPDATE=`cat $logfile1 | egrep -i "Update" | sed 's/ */ /g' | cut -d" " -f2` I need soming like below: if value is null... (8 Replies)
Discussion started by: Veera_V
8 Replies

4. UNIX for Advanced & Expert Users

Insertion of Null Character while writing into file

I have a huge file with record length around 5000 characters. There is an ETL tool datastage which is writing this data to the file(AIX server). At position 4095 i have seen NULL Character(^@). when i am using this command "head -1 file_nm | sed 's/\000//g'" --- the output is displaying... (3 Replies)
Discussion started by: issaq84mohd
3 Replies

5. Shell Programming and Scripting

Insert string 'NULL' where there is a null value

I have an input file having 7 fields delimited by , eg : 1,ABC,hg,1,2,34,3 2,hj,YU,2,3,4, 3,JU,kl,4,5,7, 4,JK,KJ,3,56,4,5 The seventh field here in some lines is empty, whereas the other lines there is a value. How do I insert string NULL at this location (7th loc) for these lines where... (8 Replies)
Discussion started by: zilch
8 Replies

6. Programming

Question about NULL Character & fgets()

Assume client send the message " Hello ", i get output such as Sent mesg: hello Bytes Sent to Client: 6 bytes_received = recv(clientSockD, data, MAX_DATA, 0); if(bytes_received) { send(clientSockD, data, bytes_received, 0); data = '\0';... (2 Replies)
Discussion started by: f.ben.isaac
2 Replies

7. UNIX for Dummies Questions & Answers

Using /dev/null with grep and find

Hi, I am trying to display the filename in which a string was found after using find and grep. For this after some googling I found that this works: find -name "*.java" -exec grep "searchStr" {} /dev/null \; I wanted to know the difference between the above and the following: find -name... (0 Replies)
Discussion started by: gaurav_s
0 Replies

8. Shell Programming and Scripting

Null Character Handling

Hi All, I have a problem with Null values while reading line by line from a text file. I wrote a shell script to read set of file names from a text file line by line, and zipping the each individual file and copying those zip files into some separate directory, and removing the original file... (3 Replies)
Discussion started by: npk2210
3 Replies

9. UNIX for Dummies Questions & Answers

Find files which contain a null character

Hi, I would like to use grep to find files which contain NULL characters. I'm not sure how to represent the null character in the grep statement. Could anyone help please? Thanks! Helen :confused: (5 Replies)
Discussion started by: Bab00shka
5 Replies

10. UNIX for Advanced & Expert Users

sending a null character to a terminal

I'm testing out some ESMTP AUTH stuff, and it requires that the username and password be on the same line separated by a null character. Does anyone know how to echo the ASCII null character? Thanks, Alex (3 Replies)
Discussion started by: vertigo23
3 Replies

Featured Tech Videos