Manipulation of a list

Thread Tools Search this Thread
# 8  
i had a server a while back that got bogged down every night because a job catted a large log file (>2gb) and piped that output to grep ... it was only when i stayed up overnight to trace this job when we found out what the issue was ... removing the cat pipe fixed the job ...
# 9  
In the unix world I would not expect "grep filename" to outperform "cat filename| grep" on large files unless there was some bottleneck in the system.
The relevant unix commands are optimised for processing from a pipeline, with processing from a file as an exception. However I have noticed that "grep" and "sed" have much improved file handling in newer versions.

Just remembered a unix SVR3 system where "cat | grep" was chronically slow when straight "grep" was not. Had to increase disc buffer space in the kernel because default disc buffer settings were absurdly low to allow for the manufacturers "minimum system".

Last edited by methyl; 01-03-2012 at 08:59 PM.. Reason: rewrite
# 10  
@kristinu O/P
Is this similar to one of your other threads?
# 11  
One I only wanted a sort in order, the other is to remove part of an entry from all entries in a list and ensuring the remaining fields are identical.
# 12  
Thanks for the explanation.

Previous Thread | Next Thread
Thread Tools Search this Thread
Search this Thread:
Advanced Search

Test Your Knowledge in Science: Gadgets
Difficulty: Medium
The Western Electric Model 500 telephone uses tone dialing to dial phone numbers.
True or False?

10 More Discussions You Might Find Interesting

1. Shell Programming and Scripting

Column manipulation

Hallo Team, I have a .csv file. I would like to have another column called Prefix. Under column Prefix i would like to have the first 3 numbers from the theird column. Other Licenced Operator Alpha Code Numbering Per minute Interconnect Fee per rate group (R Excluding VAT) ... (4 Replies)
Discussion started by: kekanap
4 Replies

2. UNIX for Dummies Questions & Answers

text manipulation help

Hello, How can I replace in a text document a space " " with ":"? (3 Replies)
Discussion started by: galford
3 Replies

3. Windows & DOS: Issues & Discussions

Excel manipulation

I have a .csv file, when i open it in excel sheet the content is getting displayed in scientific notation (E+e.) , now inorder to remove tht i have appended ' (single quote) infront of the number. This is working fine. But when i open in excel the ' single quote is appearing before the number. My... (1 Reply)
Discussion started by: dvrraju
1 Replies

4. Shell Programming and Scripting

String manipulation

Hi All, Pls help me out on the below, 05 LAMSZ201-ZM-MEMO2-DATE02-5 PIC X(10). 05 LAMSZ201-ZM-MEMO2-AMT02-5 PIC S9(13)V99. 05 LAMSZ201-ZM-MEMO2-TYPE02-6 PIC XXX. 05 LAMSZ201-ZM-MEMO2-DATE02-6 PIC X(10). 05 ... (2 Replies)
Discussion started by: baskivs
2 Replies

5. Shell Programming and Scripting

Line manipulation

hi guys, I have wrote a code to essentially to scan line by line and extract the epoch time and count value. I was able to compare the line time with current time and make an if condition statement to increase count but I m having problems replacing the old count with the new count value. I know... (3 Replies)
Discussion started by: abilash.amara
3 Replies

6. Shell Programming and Scripting

String Manipulation

How u convert string "hi pravin how are you?" to "Hi Pravin How Are You?" (4 Replies)
Discussion started by: proactiveaditya
4 Replies

7. Shell Programming and Scripting

Date manipulation

Hi Gurus, How to minus 15 minuets from current system time. For example if current time is " Wed Oct 14 12:12:38 BST 2009", i need "Wed Oct 14 11:57:38 BST 2009" Thanks (2 Replies)
Discussion started by: kumarmani
2 Replies

8. Shell Programming and Scripting

Splitting a list @list by space delimiter so i can access it by using $list[0 ..1..2]

EDIT : This is for perl @data2 = grep(/$data/, @list_now); This gives me @data2 as Printing data2 11 testzone1 running /zones/testzone1 ***-*****-****-*****-***** native shared But I really cant access data2 by its individual elements. $data2 is the entire list, while $data,2,3...... (1 Reply)
Discussion started by: shriyer
1 Replies

9. Shell Programming and Scripting

Subtract 100 from first field in long list? Simple manipulation?

It sounds so easy to do. I have a file thats laid out like this.. number text text text text (etc about 15 times with various text fields) I want to take the first field, "number", subtract 100 from it, and then put it back in the file. a simple little manipulation of the first field in... (4 Replies)
Discussion started by: LordJezo
4 Replies

10. UNIX for Dummies Questions & Answers


hi, i have got a table with n number of rows and 2 can i get get 1 row at a time using any unix command without copying to any file? Thanks and Regards vivek.s (13 Replies)
Discussion started by: vivekshankar
13 Replies

Featured Tech Videos