Login or Register to Ask a Question and Join Our Community

Sponsored Content
Full Discussion: Read input and output redirection filename within a script
Top Forums Shell Programming and Scripting Read input and output redirection filename within a script Post 302454403 by hedonist12 on Saturday 18th of September 2010 02:57:39 AM
Old 09-18-2010
Read input and output redirection filename within a script
Hello everyone,
My requirement is that within a script I need to construct the command line exactly that it was invoked with. For example :
Code:
sh a.sh arg1 arg2 arg3 < input.txt > output.txt

Now within a.sh, I construct a file which has these contents "
Code:
sh a.sh arg1 arg2 arg3 < input.txt > output.txt"

With positional parameters, I can build the argument list but the input and output redirection filenames get lost.

Essentially, a.sh can be invoked with or without "<" , ">". I remember I was able to do it once in the past using read command. Struggling to recollect it now.

I need this because I want to overload a.sh. Our scripts call it umpteen number of times. So, I need to avoid changing those calls and still make a.sh behave differently.

Any help whall be greatly appreciated.
Last edited by Scott; 09-18-2010 at 03:34 PM.. Reason: Please use CODE tags
 

10 More Discussions You Might Find Interesting

1. Shell Programming and Scripting

Asking about shell script input output redirection

Hi, Can anyone please tell me what these lines do? ls >& outfile ls outfile 2>&1 Thanks. (1 Reply)
Discussion started by: trivektor
1 Replies

2. Programming

read input-process-output

Can you help me ? I want to write a program ,which can open a input file (input.txt) and run as child process ,then write to output file (output.txt)....... char inFile="input.txt"; char outFile="output.txt"; int main(int argc, char **argv) { pid_t pid=1; int no=0; // no. of... (5 Replies)
Discussion started by: cupid1575
5 Replies

3. Shell Programming and Scripting

How to check for Input Redirection in my script?

All, I have a requirement to write a script where I check for Input redirection when the script was executed, based on which I handle my logic. Below is the example: my.script #! /bin/ksh # Not sure how to frame the if condition below if ; then echo "Input Redirected from a file" ... (7 Replies)
Discussion started by: bharath.gct
7 Replies

4. Shell Programming and Scripting

use input filename as an argument to name output file

I know this is a simple matter, but I'm new to this. I have a shell script that calls a sed script from within it. I want the output of the shell script to be based on the input file I pass as an argument to the original script. In other words... ./script.sh file.txt (script.sh calls sed... (2 Replies)
Discussion started by: estebandido
2 Replies

5. Shell Programming and Scripting

Script to read input and output files and child scripts

I have a directory where i have *.sas; *.pl;*.sh and *.c scripts I need to find out what are the child scripts and input output files for each script: say I have a shell script which calls a perl script and a sas script: In my first line I want I a) the parent script name; b) the... (1 Reply)
Discussion started by: ramky79
1 Replies

6. Shell Programming and Scripting

Print output and read input on same line

How do I print output and read input on the same line in ksh? echo Hello, what is your name? read name (1 Reply)
Discussion started by: robin_simple
1 Replies

7. Shell Programming and Scripting

Input redirection script

Hi, #!/bin/bash while ; do rm -f /tmp/pipe mkfifo /tmp/pipe ./yuv4mpeg_to_v4l2 < /tmp/pipe & mplayer tom_and_jerry.mp4 -vf scale=480:360 -vo yuv4mpeg:file=/tmp/pipe sleep 65; done When I run this - after mplayer finishes playing video it says - Exiting... (End of... (2 Replies)
Discussion started by: ashokvpp
2 Replies

8. Shell Programming and Scripting

Input redirection within bash script

Hi, when I try to redirect input and the command is described as a string within an array redirection does not work. why? #!/bin/bash dir=("tail < ./hello.txt") tail < ./hello.txt #works ${dir} #does not work (2 Replies)
Discussion started by: heinzel
2 Replies

9. Shell Programming and Scripting

Use while loop to read file and use ${file} for both filename input into awk and as string to print

I have files named with different prefixes. From each I want to extract the first line containing a specific string, and then print that line along with the prefix. I've tried to do this with a while loop, but instead of printing the prefix I print the first line of the file twice. Files:... (3 Replies)
Discussion started by: pathunkathunk
3 Replies

10. Shell Programming and Scripting

Read input write multply output with creteria

Hi All Please Help Read input write multply output with creteria Exemple i have file abc 111 444 abc 111 444 def 111 444 def111 444 bbb 111 444 bbb 111 444 i would need write 3 files pos 1-3 is the Criteria output would be file1 contains abc file2 def file3 bbb ... (3 Replies)
Discussion started by: tonyk334
3 Replies

LEARN ABOUT CENTOS

afquerylong

AFQUERY(3)																AFQUERY(3)

NAME

       afQuery, afQueryLong, afQueryDouble, afQueryPointer - query the capabilities of the Audio File Library

SYNOPSIS

       #include <audiofile.h>

       AUpvlist afQuery (int querytype, int arg1, int arg2, int arg3, int arg4);

       long afQueryLong (int querytype, int arg1, int arg2, int arg3, int arg4);

       double afQueryDouble (int querytype, int arg1, int arg2, int arg3,
	   int arg4);

       void *afQueryPointer (int querytype, int arg1, int arg2, int arg3,
	   int arg4);

PARAMETERS

       querytype can be one of the following:

       o    AF_QUERYTYPE_FILEFMT

       o    AF_QUERYTYPE_INST

       o    AF_QUERYTYPE_INSTPARAM

       o    AF_QUERYTYPE_COMPRESSION

       o    AF_QUERYTYPE_COMPRESSIONPARAM

       o    AF_QUERYTYPE_MISC

       o    AF_QUERYTYPE_MARK

       o    AF_QUERYTYPE_LOOP

       arg1, arg2, arg3, and arg4 are integer selectors whose meaning depends upon querytype.

RETURN VALUE

       Upon success, afQuery will return a non-null AUpvlist value. Upon failure, afQuery will return null while afQueryLong and afQueryDouble
       will return -1 and afQueryPointer will return null.

       Pointers representing character strings are owned by the Audio File Library and must not be freed; all other pointer values must be freed
       by the caller.

DESCRIPTION

       For AF_QUERYTYPE_FILEFMT, the following selectors are valid values for arg1:

       AF_QUERY_LABEL
	   Request a short label string for the format (e.g., "aiff").

       AF_QUERY_NAME
	   Request a short name for the format (e.g., "MS RIFF WAVE").

       AF_QUERY_DESC
	   Request a descriptive name for the format (e.g., "Audio Interchange File Format").

       AF_QUERY_IMPLEMENTED
	   Request a boolean value indicating whether the format is implemented for reading and writing in the Audio File Library.

       AF_QUERY_ID_COUNT
	   Request the total number of formats implemented.

       AF_QUERY_IDS
	   Request an integer array of the id token values of all implemented file formats.

       AF_QUERY_COMPRESSION_TYPES
	   Used with the selector AF_QUERY_VALUE_COUNT in arg2, this will return a long integer containing the number of compression schemes
	   available for use within the format specified in arg3. Used with selector AF_QUERY_VALUES, it returns a pointer to an integer array
	   containing the compression id values of the compression schemes supported by the format specified in arg3.

       AF_QUERY_SAMPLE_FORMATS
	   Used with the selector AF_QUERY_DEFAULT in arg2, this will return the default sample format for the file format specified in arg3.

       AF_QUERY_SAMPLE_SIZES
	   Used with selector AF_QUERY_DEFAULT in arg2, this will return the default sample width for the file format specified in arg3.

       For AF_QUERYTYPE_INST, the following selectors are valid for arg1:

       AF_QUERY_SUPPORTED
	   Request a boolean value indicating whether the file format in arg2 supports instruments.

       AF_QUERY_MAX_NUMBER
	   Request an integer value indicating the maximum number of instruments supported by the file format in arg2.

       For AF_QUERYTYPE_INSTPARAM, the following selectors are valid for arg1:

       AF_QUERY_SUPPORTED
	   Request a boolean value indicating whether the file format in arg2 supports instrument parameters.

       AF_QUERY_ID_COUNT
	   Request an integer value indicating the number of instrument parameters supported by the file format in arg2.

       AF_QUERY_IDS
	   Request an integer array containing the instrument parameter values for the file format in arg2.

       AF_QUERY_TYPE
	   For the file format in arg2, request the type of the instrument parameter in arg3.

       AF_QUERY_NAME
	   For the file format in arg2, request the name of the instrument parameter in arg3.

       AF_QUERY_DEFAULT
	   For the file format in arg2, request the default value of the instrument parameter in arg3.

ERRORS

       afQuery can produce the following errors:

       AF_BAD_QUERYTYPE
	   The query type is unsupported.

       AF_BAD_QUERY
	   The arguments to the query are bad.

AUTHOR

       Michael Pruett <michael@68k.org>

Audio File Library 0.3.6					    03/06/2013								AFQUERY(3)
All times are GMT -4. The time now is 08:42 AM.
Unix & Linux Forums Content Copyright 1993-2022. All Rights Reserved.
Privacy Policy