Actually it *is* possible to search for patterns in a specific field with a regex only (i.e. using grep), but regexes are clumsy in this regard.
Just for completeness, here is how that is done:
If your fields are formatted, that is, record n starts at column x then it is simple a matter of including the first x-1 characters in a line (replace "<x-1>" with a number and "<pattern>" with your pattern in the regex below):
Code:
grep '^.\{<x-1>\}<pattern>' /some/file
Usually your fields are not formatted, though, but separated by some character (the "field separator", usually a comma, pipe char or a tab). Then you include the first n-1 delimiter chars (marked "<del>" below) in the search pattern:
Code:
grep '^\(.*<del>\)\{<n-1>\}<pattern>'
The "\{n\}" device in regexes is a multiplier, similar to an asterisk, but instead of "zero or more occurrences of the expression before" it says "exactly n occurrences of the expression before". There is also a variant with a range value: "\{m,n\}" means "between m and n occurrences"
Hi there,
I am trying to remove al letters after : character on specific columns from 10th column till 827. I used sed and cut to do so but I am sure there is better one liner someone can think of from unix community members.
Huge file but it has this structure (Total number of Columns =... (10 Replies)
Hi All,
I want to read an excel file.
PFA excel, I want to read the cloumn from A to G and the V to AH
starting from Row number 3.
Please help me on this. (7 Replies)
Hi all,
I have a large matrix of 720 x 25. I want to get sum of range of rows and columns. Like, I need sum of all columns and row number 2 to 21, then leaving 22nd row, again sum of all columns and row number 23 to 42 again leaving 43rd row and then sum of 44th to 63. Means I want to add all... (4 Replies)
I want to find all files under /var directory that refer to any ip from 10.1.1.1 to 10.1.1.255 using grep. How can this be done.
Please help (5 Replies)
hey,
i need to grep / awk a list of "DEV ID" range for example for greping
0936 - 09C1 from this file:
0x5000097310036d05 558 1 20531 LOCAL GLOBAL 42048000 YES 0x8e36c8bd07ce9e13 DEV ID: 0933
0x5000097310036d05 559 1 20531 ... (1 Reply)
Dear all,
there is a nice solution for a text merge where the second file has only variables with a numeric range ( sorry, cannot post URL + thread is closed ). The real world is however more complicated than in the earlier example.
file1
A 1
A 2
A 3
B 1
B 2
B 3
B 4
C 1
C 2
C 3
C... (4 Replies)
I have a huge matrix file which looks like this (example matrix):
1 2 3 5
4 5 6 7
7 6 8 9
1 2 4 2
7 6 5 1
3 2 1 9
As one can see, this matrix has 4 columns and 6 rows. But my original matrix has some 3 million rows and 6000 columns.
For example, on this matrix I can define my task as... (2 Replies)
Hi,
I have a query about joining files using data ranges.
Example files below - I want to join file1 to file2 with matches where file1 column 1 is equal to file2 column1, and file1 column 2 is within the range of file2 columns 3 and 4. I would like rows which don't match to be printed too.
... (4 Replies)
