No way would I use a shell for that job! The following Perl script is probably a hundred times faster and more efficient!
While I agree that Perl is usually well suited for this type of application, I do not think this generalization is accurate. The shell scripts above are fine but there is room for some significant speed optimizations. If we use ksh (ksh93s+) instead of bash and a method that resembles the one in your Perl script, I think there would not be a real big difference in speed.
filter.ksh93
Last edited by Scrutinizer; 08-29-2009 at 05:32 PM..
Hi There,
I've written a script that processes a data file on our system. Basically the script reads a post code from a list file, looks in the data file for the first occurrence (using grep) and reads the line number. It then tails the data file, with the line number just read, and outputs to a... (3 Replies)
I'm trying to find a command which will allow me to remove a range of lines (2-4) from a .dat file from the command line without opening the file.
Someone mentioned using the ex command?
Does anyone have any ideas?
thanks (6 Replies)
Hi Gurus,
I'm a little new to UNIX. How can I do remove the first and last line in a file? Say, supppose I have a file as below:
Code:
1DMA
400002BARRIE
401002CALGARY/LETHBRI
402002CARLETON
500001PORTLAND-AUBRN
501001NEW YORK, NY
502001BINGHAMTON, NY ... (2 Replies)
Hi folks, I have a long string of DNA sequences, and I need to remove several lines, as well as the line directly following them. For example, here is a sample of my starting material:
>548::GY31UMJ02DLYEH rank=0007170 x=1363.5 y=471.0 length=478... (1 Reply)
Hi there, normally if I want to remove a user tht I have added to a specific group, i would do the following
this is what my group2 looks like
# grep group2 /etc/group
group2:x:7777:user2,user1,user4
user1 has been defined in a few groups
# id -nG user1
group1 group2 group3
So... (3 Replies)
I have a reference file that needs to remain static and another file that may or may not have duplicate rows that match the reference file. I need help with a command that will delete any duplicate rows from the second file while leaving reference file intact
For example reference file would... (4 Replies)
Hello Everyone,
I'm currently have a requirement where I've generated a list of files with specific attributes and I need to know what lines are similar between the two files. For example:
-File 1-
line1
line2
line3
-File 2-
line1
line2
line4
line5
-Desires Output-
line1
line2... (5 Replies)
Hi,
I have a linux server that was hacked and I have a bunch of files that sporadically contain the following lines through out the file:
<?php eval(base64_decode("Xxxxxxxxxxxxxx/xxxxxxxx"));
I did't put the exact lines of the file in this post. The "Xxxx" are random letters/numbers.... (8 Replies)
I have a file `/tmp/wrk` containing filenames with paths. I want to remove filenames
from this file, for example
remove all filenames containing alja cagr cavt clta cmdo or corl
remove all filenames containing data for days in region `d.2016.001` to `d.2016.207`
remove all filenames... (10 Replies)
Discussion started by: kristinu
10 Replies
LEARN ABOUT OPENSOLARIS
let
let(1) User Commands let(1)NAME
let - shell built-in function to evaluate one or more arithmetic expressions
SYNOPSIS
ksh
let arg...
ksh93
let [expr...]
DESCRIPTION
ksh
Each arg is a separate arithmetic expression to be evaluated.
ksh93
let evaluates each expr in the current shell environment as an arithmetic expression using ANSI C syntax. Variables names are shell vari-
ables and they are recursively evaluated as arithmetic expressions to get numerical values. let has been made obsolete by the ((...)) syn-
tax of ksh93(1) which does not require quoting of the operators to pass them as command arguments.
EXIT STATUS
ksh
ksh returns the following exit values:
0 The value of the last expression is non-zero.
1 The value of the last expression is zero.
ksh93
ksh93 returns the following exit values:
0 The last expr evaluates to a non-zero value.
>0 The last expr evaluates to 0 or an error occurred.
ATTRIBUTES
See attributes(5) for descriptions of the following attributes:
+-----------------------------+-----------------------------+
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
+-----------------------------+-----------------------------+
|Availability |SUNWcsu |
+-----------------------------+-----------------------------+
SEE ALSO ksh(1), ksh93(1), set(1), typeset(1), attributes(5)SunOS 5.11 2 Nov 2007 let(1)