In general, calling cat with just one argument is a useless use of cat. Instead of running cat 3 times, just do:
Code:
cat header datafile footer > file1.txt
That's a bit more optimized than your way.
Beyond that, no; there's no UNIX system call to insert data before other data in a file, and I don't know a system that does. Nor is there a faster form of read() than the general purpose one, why would anyone ever use the "slow" one?
If whatever's using these datafiles can accept input on stdin, you could generate them at runtime to avoid the extra reads and wasted storage:
Code:
cat header datafile footer | command
Last edited by Corona688; 05-11-2010 at 02:11 PM..
I have a flat file and need to count no of records in the file less the header and the trailer record.
I would appreciate any and all asistance
Thanks
Hadi Lalani (2 Replies)
All,
I am new to unix and i have the following requirement.
I have file(s) landing into input directory with timestamp, first i want to copy all these files into seperate directory then i want to rename these files without timestamp and also remove header,trailer from that file..
Could... (35 Replies)
Hi All,
I am karthik. I am new to this forum. I have one requirement.
I have a file with header and footer.
Header may be like
HDR0001
or
FILE20090110
(Assume it is unknown so far, but i am sure there is a header in the file)
likewise file has the trailer too.
I just... (7 Replies)
How can we a shell script and pass date parameters .I have 3 files comming from Datastage with |" delimited
I need append 3 files as above: File1:
P0000|"47416954|"AU|"000|"INS|"0000|"|"20060601|"99991231|"|"|"|"|"01
File 2:... (2 Replies)
Hi,
I want to add the below Header to all the files in sequence File1,File2,File3...etc
"ABC,<number of chracter in the file>"
e,g - If File1 is as below
pqrstuvdt
abcdefgh
then I want to add the above header into it ,So that File1 becomes as below
ABC,17
pqrstuvdt
abcdefgh
... (9 Replies)
Hi All,
I am trying write a simple command using AWK and SED to this but without any success.
Here is what I am using:
head -1 test1.txt>test2.txt|sed '1d;$d' test1.txt|awk '{print substr($0,0,(length($0)-2))}' >>test2.txt|tail -1 test1.txt>>test2.txt
Input:
Header
1234567
abcdefgh... (2 Replies)
Hi,
I need a script that validates a file header/detail/trailer. File layout is:
Header - Rec_Type|File_name|File_Date
Detail - Rec_Type|field1|field2|field3...
Trailder - Rec_Type|File_name|File_Date|Record_count
Sample Data:
HDR|customer_data.dat|20120709... (7 Replies)
I need to split the file based on pattern from position 34-37 while retaining the header and trailer records in each individual split file
Also is it possible to output the TOM and PAT records in the same output file ?
I need the output file names same as xyz_pattern_Datetimestamp.txt
... (23 Replies)
I have a EBCDIC multi layout file which has a header record which is 21 bytes, The Detail records are 2427 bytes long and the trailer record is 9 bytes long.
Is there a command to remove the header as well as trailer record and read only the detail records while at the same time not altering... (1 Reply)
Discussion started by: abhilashnair
1 Replies
LEARN ABOUT LINUX
cat
CAT(1) User Commands CAT(1)NAME
cat - concatenate files and print on the standard output
SYNOPSIS
cat [OPTION]... [FILE]...
DESCRIPTION
Concatenate FILE(s), or standard input, to standard output.
-A, --show-all
equivalent to -vET
-b, --number-nonblank
number nonempty output lines
-e equivalent to -vE
-E, --show-ends
display $ at end of each line
-n, --number
number all output lines
-s, --squeeze-blank
suppress repeated empty output lines
-t equivalent to -vT
-T, --show-tabs
display TAB characters as ^I
-u (ignored)
-v, --show-nonprinting
use ^ and M- notation, except for LFD and TAB
--help display this help and exit
--version
output version information and exit
With no FILE, or when FILE is -, read standard input.
EXAMPLES
cat f - g
Output f's contents, then standard input, then g's contents.
cat Copy standard input to standard output.
AUTHOR
Written by Torbjorn Granlund and Richard M. Stallman.
REPORTING BUGS
Report cat bugs to bug-coreutils@gnu.org
GNU coreutils home page: <http://www.gnu.org/software/coreutils/>
General help using GNU software: <http://www.gnu.org/gethelp/>
Report cat translation bugs to <http://translationproject.org/team/>
COPYRIGHT
Copyright (C) 2010 Free Software Foundation, Inc. License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>.
This is free software: you are free to change and redistribute it. There is NO WARRANTY, to the extent permitted by law.
SEE ALSO
The full documentation for cat is maintained as a Texinfo manual. If the info and cat programs are properly installed at your site, the
command
info coreutils 'cat invocation'
should give you access to the complete manual.
GNU coreutils 8.5 February 2011 CAT(1)