More efficient with awk:
Would be even shorter with perl, thanks to its -i option and internal sort.
I'd have to do some benchmarking to see if sed, sed | sort is slower than using awk to invoke sh to invoke sort; since there are three fork() and exec family (or spawn()) calls either way; but I like the concept.
But, shouldn't:
be:
in your script?
This User Gave Thanks to Don Cragun For This Post:
Hello,
I have a header which I have to add to a sorted file, however if I use
cat header sortedfile > newfile, the operation takes 2 minutes as the sorted file is over 400mb.
I have noticed that when I sort the 400mb unsorted file, this only takes 14 seconds to create the output.
As... (2 Replies)
So, I have a file that has some duplicate lines. The file has a header line that I would like to keep at the top.
I could do this by extracting the header from the file, 'sort -u' the remaining lines, and recombine them. But they are quite big, so if there is a way to do it with a single... (1 Reply)
Hi,
Please help with this problem. Somehow does not work for me.
test.txt
CHR SNP BP A1 C_A C_U A2 CHISQ P OR
19 rs10401969 19268718 C 222 890 T 0.03462 0.8524 0.9857
1 rs10873889 ... (4 Replies)
Hi Experts,
I want to Sort the data in fixed width file where i have Header and Footer also in file.
I m using below commad to do the sort based on field satarting from 15 position to 17 position , but it is not ignoring the Header and Footer of the file while sorting. In the output i am... (5 Replies)
I am having report file with header and footer . The details in between header and footer are separated by a pipe charater. I want to sort the file by considering multiple columns in between header and footer.
pls help (4 Replies)
How to sort a tab delimited file first on col1 and then on col2. Also I need to keep the header intact.
file.txt
val1 val2 val3 val4
a b c d
m n o p
e f g h
i j k l
... (3 Replies)
Hi,
I'm trying to sort 2 different .txt tab delimited files with the command line:
sort -k 1b,1 inputfile > outputfile
But doing that i'm also sorting the header (that ends at the end of my file).
How can i sort a .txt file without sorting the header but conserving the header in the... (3 Replies)
I have several las files with a header and each file start Version and text and before the data starts end up with ~Ascii, then the numbers starts:
-------------------------------------------------------------------------
Code:
~Version
.....text....
~Ascii
2 abc 230 1 name
1 abc ... (1 Reply)
Hi,
I am using SUN SOLARIS (SunOS sun4v sparc SUNW, T5240).
I have a huge data file with header and trailer. This file gets used into an ETL process. ETL skips the header record (which is the first record of the file) and loads the rest of the record. The file can be delimited (comma,... (5 Replies)
Hi ,
My UNIX system is SUN Solaris.
I am trying to do a simple thing as described below.
I have a PIPE delimited file that has header and trailer. So the file is something like below:
Test1.txt looks like something below:
field_data1|field_data2|and some more data --Header
... (5 Replies)
Discussion started by: Saanvi1
5 Replies
LEARN ABOUT NETBSD
in_cksum
IN_CKSUM(9) BSD Kernel Developer's Manual IN_CKSUM(9)NAME
in_cksum, in4_cksum, in6_cksum -- compute Internet checksum
SYNOPSIS
uint16_t
in_cksum(struct mbuf *m, int len);
uint16_t
in4_cksum(struct mbuf *m, uint8_t nxt, int off, int len);
uint16_t
in6_cksum(struct mbuf *m, uint8_t nxt, int off, int len);
DESCRIPTION
These functions are used to compute the ones-complement checksum required by IP and IPv6. The in4_cksum() function is used to compute the
transport-layer checksum required by tcp(4) and udp(4) over a range of bytes starting at off and continuing on for len bytes within the mbuf
m.
If the nxt parameter is non-zero, it is assumed to be an IP protocol number. It is also assumed that the data within m starts with an IP
header, and the transport-layer header starts at off; a pseudo-header is constructed as specified in RFC768 and RFC793, and the pseudo-header
is prepended to the data covered by the checksum.
The in6_cksum() function is similar; if nxt is non-zero, it is assumed that m starts with an IPv6 header, and that the transport-layer header
starts after off bytes.
The in_cksum() function is equivalent to in4_cksum(m, 0, 0, len).
These functions are always performance critical and should be reimplemented in assembler or optimized C for each platform; when available,
use of repeated full-width add-with-carry followed by reduction of the sum to a 16 bit width usually leads to best results. See RFC's 1071,
1141, 1624, and 1936 for more information about efficient computation of the internet checksum.
RETURN VALUES
All three functions return the computed checksum value.
SEE ALSO inet(4), inet6(4), tcp(4), udp(4), protocols(5), mbuf(9)STANDARDS
These functions implement the Internet transport-layer checksum as specified in RFC768, RFC793, and RFC2460.
BUGS
The in6_cksum() function currently requires special handling of link-local addresses in the pseudo-header due to the use of embedded scope-
id's within link-local addresses.
BSD May 22, 2001 BSD