Scrutinizer is correct, but as there are always several ways in Unix to do something, you could do it with the exec too, if you use ksh (note that this won't work in bash, because bash doesn't have the print command):
This way you won't have to take care of the first ">" and subsequent ">>" redirections (if you mistakenly use ">" it will clear the file) and you will not have to repeat the output files name over and over again.
You could even influence the content of your output file with some program logic in the script - something the here-document provides little support for. For instance, the following would not be possible with a here-doc:
In exchange for helping you I'd like to ask you to learn about I/O channels (file descriptors) and redirection in Unix and how to use these. You might want to read this thread as a starter.
Hello. I have one file that is a collection of discarded emails. Each email is it's own section with each section beginning with the same header (ie 'Another Email' ). I want to traverse through the file and every time I find the header ('Another Email') I then want to pick out the 'To:' line... (5 Replies)
I need to write value of variable $version at a particular line in a text file.
Line number is determined by another variable &line......I don't know how to do it in shell script ... (2 Replies)
I need to put together a RAID1 file server for use by Windoze systems. I've built zillions of windows systems from components. I was a HPUX SE for a long time at HP, but have been out of the game for years.
I've got an old workhorse mobo FIC PA-2013 with a 450 MHz K6 III+ I could use, but I'd... (2 Replies)
Hi,
I have two text files. Need to create a third text file extracting specific data from first two existing files..
Text File 1: Format contains:
SQL*Loader: Release 10.2.0.1.0 - Production on Wed Aug 4 21:06:34 2010
some text ............so on...and somwhere text like:
Record 1:... (1 Reply)
Hi,
I know the code to write a piece of text to the end of a given text file is
echo $text >> filename.txt
I would like to know how to write a piece of text to a file using shell, but the file name isn't given. I want it to write to whatever text file is currently open. Not to all text files... (2 Replies)
I am having a file, around 500 lines. which contains one letter words, two letters words,...and so on(up to 15 letter words and words are not seprated by line). I need to compare all 1 letter words with 3,4,5 and 6 letters word, all 2 letters words with 2,3,4 and 5 letters words and all 3 letters... (3 Replies)
Hi,
I am trying to populate an array with data from a text file. I have a working method using awk but it is too slow and inefficent. See below.
The text file has 70,000 lines. As awk is a line editor it reads each line of the file until it gets to the required line and then processes it.... (3 Replies)
I have a list of files defined in a single file , one on each line.(No.of files may wary each time)
eg. content of ETL_LOOKUP.dat
/data/project/randomname
/data/project/ramname
/data/project/raname
/data/project/radomname
/data/project/raame
/data/project/andomname
size of these... (5 Replies)
I have one array SPLNO with approx 10k numbers.Now i want to search the subscriber number from MDN.TXT file (containing approx 1.5 lac record)from the array.if subscriber number found in array it will perform below operation.my issue is that it's taking more time because for one number it's search... (6 Replies)
Shell: sh/bash
OS: Linux (all unix flavors)
Suppose i have a variable with this content:
ArgZ='
import os
import sys
MySpecialpath = os.path.abspath(sys.argv)
#
'
ArgZB='#REGEN
#REGEN
#REGEN
'
I want to add this text to a file/script, only under the following conditions:
1. ... (1 Reply)
Discussion started by: SkySmart
1 Replies
LEARN ABOUT SUNOS
source
exec(1) User Commands exec(1)NAME
exec, eval, source - shell built-in functions to execute other commands
SYNOPSIS
sh
exec [argument...]
eval [argument...]
csh
exec command
eval argument...
source [-h] name
ksh
*exec [arg...]
*eval [arg...]
DESCRIPTION
sh
The exec command specified by the arguments is executed in place of this shell without creating a new process. Input/output arguments may
appear and, if no other arguments are given, cause the shell input/output to be modified.
The arguments to the eval built-in are read as input to the shell and the resulting command(s) executed.
csh
exec executes command in place of the current shell, which terminates.
eval reads its arguments as input to the shell and executes the resulting command(s). This is usually used to execute commands generated as
the result of command or variable substitution.
source reads commands from name. source commands may be nested, but if they are nested too deeply the shell may run out of file descrip-
tors. An error in a sourced file at any level terminates all nested source commands.
-h Place commands from the file name on the history list without executing them.
ksh
With the exec built-in, if arg is given, the command specified by the arguments is executed in place of this shell without creating a new
process. Input/output arguments may appear and affect the current process. If no arguments are given the effect of this command is to mod-
ify file descriptors as prescribed by the input/output redirection list. In this case, any file descriptor numbers greater than 2 that are
opened with this mechanism are closed when invoking another program.
The arguments to eval are read as input to the shell and the resulting command(s) executed.
On this man page, ksh(1) commands that are preceded by one or two * (asterisks) are treated specially in the following ways:
1. Variable assignment lists preceding the command remain in effect when the command completes.
2. I/O redirections are processed after variable assignments.
3. Errors cause a script that contains them to abort.
4. Words, following a command preceded by ** that are in the format of a variable assignment, are expanded with the same rules as a vari-
able assignment. This means that tilde substitution is performed after the = sign and word splitting and file name generation are not
performed.
EXIT STATUS
For ksh:
If command is not found, the exit status is 127. If command is found, but is not an executable utility, the exit status is 126. If a redi-
rection error occurs, the shell exits with a value in the range 1-125. Otherwise, exec returns a zero exit status.
ATTRIBUTES
See attributes(5) for descriptions of the following attributes:
+-----------------------------+-----------------------------+
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
+-----------------------------+-----------------------------+
|Availability |SUNWcsu |
+-----------------------------+-----------------------------+
SEE ALSO csh(1), ksh(1), sh(1), attributes(5)SunOS 5.10 17 Jul 2002 exec(1)