Login or Register to Ask a Question and Join Our Community

Sponsored Content
Full Discussion: Reading from file bash command
Top Forums Shell Programming and Scripting Reading from file bash command Post 303003169 by rbatte1 on Friday 8th of September 2017 12:01:26 PM
Old 09-08-2017
If you want to add a default/dummy within a bash script, you could do this:-
Code:
my_var="${my_var:-default}"

This says "assign the value of $my_var to itself, or the string default if it is empty or not set." You can have another variable instead of the string default if you want to.


Does that help?



Robin
 

10 More Discussions You Might Find Interesting

1. Shell Programming and Scripting

Bash: Reading 2 arguments from a command line

If no arguments are entered I wanna be able to read 2 arguments, i have done like this but it doesnt work: x=0 until #loop starts do if ; then echo No arguments were entered, please enter 2 arguments. read $1 $2 elif || ; then echo $#... (0 Replies)
Discussion started by: Vozx
0 Replies

2. Shell Programming and Scripting

bash: reading filenames from file

Hi, I'm trying to write a script that reads filenames from a file and use these filenames in a loop. The filenames are all on one line and the problem is that these filenames have wildcards like * and braces like in them. Right now what I'm doing is something like this: echo "reading from... (0 Replies)
Discussion started by: warp17
0 Replies

3. Shell Programming and Scripting

Reading lines from a file, using bash, "at" command

Hi. I have the script shown below. If I execute it form the command line it seems to work properly, but when I fun it using the unix "at" command "at -m now < ./kill-at-job.sh" It appears to hang. Below is the script, the input file, and the execution as reported in the e-mail from the "at"... (3 Replies)
Discussion started by: jbsimon000
3 Replies

4. Shell Programming and Scripting

Problem in reading file (bash)

i get a name from user first name : last name, in this format. Now i am saving this to a file. what i want is, I do not want to save any name if I already have one entry o that same name..what should i do for example user give robert fernandez this will save in file as robert:fernandez. if... (5 Replies)
Discussion started by: Learnerabc
5 Replies

5. Shell Programming and Scripting

Help in reading a cv file in bash

Hi All, I am trying to read a .csv file which has some 6 columns. Eg: samp.csv one, two, three, four six, seven, eight, nine I used the following code, for line in `cat samp.csv` do echo "$line" done It displays every comma seperated values in each line like, one,... (1 Reply)
Discussion started by: johnwilliams.sp
1 Replies

6. Shell Programming and Scripting

Bash: Reading a file and assigning variables from file

I have a file that has four values on each line and I'd like to give each column a variable name and then use those values in each step of a loop. In bash, I believe you could use a while loop to do this or possibly a cat command, but I am super new to programming and I'm having trouble decoding... (2 Replies)
Discussion started by: ccorder22
2 Replies

7. Shell Programming and Scripting

Reading command line options from bash script

I have the following code and I am calling it using ./raytrac.bash -u and getting problems. For some reason opt_usage is still 0. opt_usage=0 iarg=0 narg=$# while (($iarg < $narg)) do (( iarg = $iarg + 1 )) arg=$argv usrInputFlag=`echo $arg | awk '/=/ {print 1}; ! /=/... (22 Replies)
Discussion started by: kristinu
22 Replies

8. Shell Programming and Scripting

Reading a text file using bash

I've a file in linux with following text: ;ip address hostname put-location alt-put-location tftpserver 192.168.1.1 r01-lab1-net /mnt/nas1/fgbu/ /opt/fgbu/devicebackup 192.168.1.254Now I want to read these values and assign them to particular variables... (6 Replies)
Discussion started by: kashif.live
6 Replies

9. UNIX for Beginners Questions & Answers

Reading a file from a different directory in a Bash script

Hi all, Given here under a section of a script I am using. SIMDIR="/home/Ins/forces" cd $SIMDIR for file in `ls *.forces` do basename=`echo $file | sed 's/\.*$//'` extname=`echo $file | sed 's/*\(*\)\.\(.*\)/\2\1/'` echo "Processing file: "$basename python convert.py... (4 Replies)
Discussion started by: Theo Score
4 Replies

10. UNIX for Beginners Questions & Answers

Bash Variable scope - while loop while reading from a file

Cope sample1: test.sh i=0 echo " Outside loop i = $i " while do i=$(( $i + 1)) echo "Inside loop i = $i " done echo " Out of loop i is : $i " When run output : Outside loop i = 0 Inside loop i = 1 Inside loop i = 2 Inside loop i = 3 Inside loop i = 4 Inside loop i = 5 Inside... (8 Replies)
Discussion started by: Adarshreddy01
8 Replies

LEARN ABOUT MOJAVE

locale::codes::script5.18

Locale::Codes::Script(3pm)				 Perl Programmers Reference Guide				Locale::Codes::Script(3pm)

NAME

       Locale::Codes::Script - standard codes for script identification

SYNOPSIS

	  use Locale::Codes::Script;

	  $script  = code2script('phnx');		      # 'Phoenician'
	  $code    = script2code('Phoenician'); 	      # 'Phnx'
	  $code    = script2code('Phoenician',
				 LOCALE_CODE_NUMERIC);	      # 115

	  @codes   = all_script_codes();
	  @scripts = all_script_names();

DESCRIPTION

       The "Locale::Codes::Script" module provides access to standards codes used for identifying scripts, such as those defined in ISO 15924.

       Most of the routines take an optional additional argument which specifies the code set to use. If not specified, the default ISO 15924
       four-letter codes will be used.

SUPPORTED CODE SETS

       There are several different code sets you can use for identifying scripts. A code set may be specified using either a name, or a constant
       that is automatically exported by this module.

       For example, the two are equivalent:

	  $script = code2script('phnx','alpha');
	  $script = code2script('phnx',LOCALE_SCRIPT_ALPHA);

       The codesets currently supported are:

       alpha, LOCALE_SCRIPT_ALPHA
	   This is a set of four-letter (capitalized) codes from ISO 15924 such as 'Phnx' for Phoenician.  It also includes additions to this set
	   included in the IANA language registry.

	   The Zxxx, Zyyy, and Zzzz codes are not used.

	   This is the default code set.

       num, LOCALE_SCRIPT_NUMERIC
	   This is a set of three-digit numeric codes from ISO 15924 such as 115 for Phoenician.

ROUTINES

       code2script ( CODE [,CODESET] )
       script2code ( NAME [,CODESET] )
       script_code2code ( CODE ,CODESET ,CODESET2 )
       all_script_codes ( [CODESET] )
       all_script_names ( [CODESET] )
       Locale::Codes::Script::rename_script  ( CODE ,NEW_NAME [,CODESET] )
       Locale::Codes::Script::add_script  ( CODE ,NAME [,CODESET] )
       Locale::Codes::Script::delete_script  ( CODE [,CODESET] )
       Locale::Codes::Script::add_script_alias	( NAME ,NEW_NAME )
       Locale::Codes::Script::delete_script_alias  ( NAME )
       Locale::Codes::Script::rename_script_code  ( CODE ,NEW_CODE [,CODESET] )
       Locale::Codes::Script::add_script_code_alias  ( CODE ,NEW_CODE [,CODESET] )
       Locale::Codes::Script::delete_script_code_alias	( CODE [,CODESET] )
	   These routines are all documented in the Locale::Codes::API man page.

SEE ALSO

       Locale::Codes
	   The Locale-Codes distribution.

       Locale::Codes::API
	   The list of functions supported by this module.

       http://www.unicode.org/iso15924/
	   Home page for ISO 15924.

       http://www.iana.org/assignments/language-subtag-registry
	   The IANA language subtag registry.

AUTHOR

       See Locale::Codes for full author history.

       Currently maintained by Sullivan Beck (sbeck@cpan.org).

COPYRIGHT

	  Copyright (c) 1997-2001 Canon Research Centre Europe (CRE).
	  Copyright (c) 2001-2010 Neil Bowers
	  Copyright (c) 2010-2013 Sullivan Beck

       This module is free software; you can redistribute it and/or modify it under the same terms as Perl itself.

perl v5.18.2							    2013-11-04						Locale::Codes::Script(3pm)
All times are GMT -4. The time now is 10:39 AM.
Unix & Linux Forums Content Copyright 1993-2022. All Rights Reserved.
Privacy Policy