Login or Register to Ask a Question and Join Our Community

Sponsored Content
Full Discussion: Make script faster
Top Forums Shell Programming and Scripting Make script faster Post 302584060 by AlbertGM on Thursday 22nd of December 2011 05:02:56 AM
Old 12-22-2011
Make script faster
Hi all,

In bash scripting, I use to read files:
Code:
cat $file | while read line; do
...
done

However, it's a very slow way to read file line by line.
E.g. In a file that has 3 columns, and less than 400 rows, like this:
Quote:
J23 21009853172000102416 15
G95 21009853122000006554 27
[...]
I run next script:
Code:
cat $line | while read line; do  ## Reads each line
   grup=`echo "$line" | cut -d " " -f3`;  ## Takes third column
   if [ "$grup" == "27" ]; then  // ## If column == "27" prints column 2. 
      exp=`echo "$line"  | cut -d " " -f2`; 
      echo $exp; 
   fi; 
done;

Using "time" command it lasts:
Quote:
real 1m49.543s
user 0m42.606s
sys 1m5.229s
It's a huge waste of time to read only less than 400 rows. Is there any way to make it faster?
Occasionally I used awk to process a file line by line, and it is much faster. Why? Any hint to read a file in bash?

Thanks a lot

Albert.
 

10 More Discussions You Might Find Interesting

1. Solaris

looking for different debugger for Solaris or to make sunstudio faster

im using the sunstudio but it is very slow , is there ant other GUI debugger for sun Solaris or at list some ways to make it faster ? im using to debug throw telnet connection connected to remote server thanks (0 Replies)
Discussion started by: umen
0 Replies

2. Shell Programming and Scripting

Can anyone make this script run faster?

One of our servers runs Solaris 8 and does not have "ls -lh" as a valid command. I wrote the following script to make the ls output easier to read and emulate "ls -lh" functionality. The script works, but it is slow when executed on a directory that contains a large number of files. Can anyone make... (10 Replies)
Discussion started by: shew01
10 Replies

3. Shell Programming and Scripting

awk help to make my work faster

hii everyone , i have a file in which i have line numbers.. file name is file1.txt aa bb cc "12" qw xx yy zz "23" we bb qw we "123249" jh here 12,23,123249. is the line number now according to this line numbers we have to print lines from other file named... (11 Replies)
Discussion started by: kumar_amit
11 Replies

4. Red Hat

Re:How to make the linux pc faster

Hi, Can any one help me out in solving the problem i have a linux database server it is tooo slow that i am unable to open even the terminial is there any solution to get rid of this problem.How to make this server faster. Thanks & Regards Venky (0 Replies)
Discussion started by: venky_vemuri
0 Replies

5. Shell Programming and Scripting

How to make copy work faster

I am trying to copy a folder which contains a list of C executables. It takes 2 mins for completion,where as the entire script takes only 3 more minutes for other process. Is there a way to copy the folder faster so that the performance of the script will improve? (2 Replies)
Discussion started by: prasperl
2 Replies

6. Shell Programming and Scripting

Running rename command on large files and make it faster

Hi All, I have some 80,000 files in a directory which I need to rename. Below is the command which I am currently running and it seems, it is taking fore ever to run this command. This command seems too slow. Is there any way to speed up the command. I have have GNU Parallel installed on my... (6 Replies)
Discussion started by: shoaibjameel123
6 Replies

7. Shell Programming and Scripting

awk changes to make it faster

I have script like below, who is picking number from one file and and searching in another file, and printing output. Bu is is very slow to be run on huge file.can we modify it with awk #! /bin/ksh while read line1 do echo "$line1" a=`echo $line1` if then echo "$num" cat file1|nawk... (6 Replies)
Discussion started by: mirwasim
6 Replies

8. Shell Programming and Scripting

How to make awk command faster?

I have the below command which is referring a large file and it is taking 3 hours to run. Can something be done to make this command faster. awk -F ',' '{OFS=","}{ if ($13 == "9999") print $1,$2,$3,$4,$5,$6,$7,$8,$9,$10,$11,$12 }' ${NLAP_TEMP}/hist1.out|sort -T ${NLAP_TEMP} |uniq>... (13 Replies)
Discussion started by: Peu Mukherjee
13 Replies

9. Shell Programming and Scripting

How to make awk command faster for large amount of data?

I have nginx web server logs with all requests that were made and I'm filtering them by date and time. Each line has the following structure: 127.0.0.1 - xyz.com GET 123.ts HTTP/1.1 (200) 0.000 s 3182 CoreMedia/1.0.0.15F79 (iPhone; U; CPU OS 11_4 like Mac OS X; pt_br) These text files are... (21 Replies)
Discussion started by: brenoasrm
21 Replies

10. Shell Programming and Scripting

How to make faster loop in multiple directories?

Hello, I am under Ubuntu 18.04 Bionic. I have one shell script run.sh (which is out of my topic) to run files under multiple directories and one file to control all processes running under those directories (control.sh). I set a cronjob task to check each of them with two minutes of intervals.... (3 Replies)
Discussion started by: baris35
3 Replies

LEARN ABOUT REDHAT

line

line(1)                                                            User Commands                                                           line(1)

NAME

       line - read one line

SYNOPSIS

       line

DESCRIPTION

       The  line utility copies one line (up to and including a new-line) from the standard input and writes it on the standard output. It returns
       an exit status of 1 on EOF and always prints at least a new-line. It is often used within shell files to read from the user's terminal.

EXIT STATUS

       Exit status is:

       0        Successful completion

       >0       End-of-file on input.

ATTRIBUTES

       See attributes(5) for descriptions of the following attributes:

       +-----------------------------+-----------------------------+
       |      ATTRIBUTE TYPE         |      ATTRIBUTE VALUE        |
       +-----------------------------+-----------------------------+
       |Availability                 |SUNWcsu                      |
       +-----------------------------+-----------------------------+

SEE ALSO

       sh(1), read(2), attributes(5)

SunOS 5.10                                                          1 Feb 1995                                                             line(1)
All times are GMT -4. The time now is 03:00 PM.
Unix & Linux Forums Content Copyright 1993-2022. All Rights Reserved.
Privacy Policy