Login or Register to Ask a Question and Join Our Community

Sponsored Content
Full Discussion: Bash: Setting default values for variables
Top Forums Shell Programming and Scripting Bash: Setting default values for variables Post 303013678 by kristinu on Sunday 25th of February 2018 08:50:10 PM
Old 02-25-2018
Bash: Setting default values for variables
I have a variable I want to use in bash script. The user will pass an argument
to the script and I will store it in `arg_fql`. If the user does not pass the variable,
I still never set arg_fql, but I set another variable to a default. However, if the user
passes a value, `arg_fql` will be set to what the user specified

I have used the following code.

Code:
[ -v arg_fql ] && fql="$arg_fql"
fql=${arg_fql:-"0.002 0.003 1 2"}

Would the following have the same effect?

Code:
fql=${arg_fql:-"0.002 0.003 1 2"}

 

10 More Discussions You Might Find Interesting

1. UNIX for Dummies Questions & Answers

Query regarding alias and setting bash as a default script

Hi All, I am setting bash as my working shell in my .profile file. So I have written a line : bash as the list line in my .profile I want to use alias as follows: alias me='who am i' When i log in, as expeced I enter the bash shell but alias doesn't work. Is it because the alias is defined... (1 Reply)
Discussion started by: VENC22
1 Replies

2. UNIX for Advanced & Expert Users

setting some variables

i have a file .NAMEexport MY_NAME=JOE when i do this at the command prompt #. .NAME $echo MY_NAME $JOEi created a script called Run.sh . .NAME At the command prompt i did #sh Run.sh #echo $MY_NAMEit returns nothing. What have i missed out? (7 Replies)
Discussion started by: new2ss
7 Replies

3. UNIX for Dummies Questions & Answers

Setting up variables

Hi all, I have a shell script that sets up the environment for an application running on UNIX - ksh. This script is run using: . ./script_name XX where XX is a parameter. I want to run it from another shell script but when I do it I don't get the envornment variables set up and the prompt... (3 Replies)
Discussion started by: solar_ext
3 Replies

4. UNIX for Advanced & Expert Users

Setting global variables with BASH/Linux

I am using functions in a script and for some strange reason the EXPORT command doesnt seem to be making my variables global. Anyone got any ideas? I am using one function to pass some output top another using the pipe command, eg Function 1 | Function 2 Function 2 reads the value... (3 Replies)
Discussion started by: gregf
3 Replies

5. Shell Programming and Scripting

[BASH] mapping of values from file line into variables

Hello, I've been struggling with this for some time but can't find a way to do it and I haven't found any other similar thread. I'd like to get the 'fields' in a line from a file into variables in just one command. The file contains data with the next structure:... (4 Replies)
Discussion started by: semaler
4 Replies

6. Shell Programming and Scripting

bash -- concatenating values from variables

Hi This is a simple one but I got a lost in translation when doing. What I want to do, given both variables in the example below, to get one value at the time from both variables, for example: 1:a 2:b etc... I need to get this in bash scripting code: varas="1 2 3 4" varbs="a b c d"... (4 Replies)
Discussion started by: ranmanh
4 Replies

7. Shell Programming and Scripting

Read record from the text file contain multiple separated values & assign those values to variables

I have a file containing multiple values, some of them are pipe separated which are to be read as separate values and some of them are single value all are these need to store in variables. I need to read this file which is an input to my script Config.txt file name, first path, second... (7 Replies)
Discussion started by: ketanraut
7 Replies

8. Shell Programming and Scripting

'Dynamic' setting of variables in bash script

Hi all, I want to dynamically set variables in a bash script. I made a naive attempt in a while loop that hopefully can clarify the idea. n=0; echo "$lst" | while read p; do n=$(($n+1)); p"$n"="$p"; done The error message is: bash: p1=line1: command not found bash: p2=line2: command... (8 Replies)
Discussion started by: jeppe83
8 Replies

9. Shell Programming and Scripting

Reading multiple values from multiple lines and columns and setting them to unique variables.

Hello, I would like to ask for help with csh script. An example of an input in .txt file is below, the number of lines varies from file to file and I have 2 or 3 columns with values. I would like to read all the values (probably one by one) and set them to independent unique variables that... (7 Replies)
Discussion started by: FMMOLA
7 Replies

10. Shell Programming and Scripting

Passing awk variables to bash variables

Trying to do so echo "111:222:333" |awk -F: '{system("export TESTO=" $2)}'But it doesn't work (2 Replies)
Discussion started by: urello
2 Replies

LEARN ABOUT CENTOS

bashbug-64

BASHBUG(1)						      General Commands Manual							BASHBUG(1)

NAME

       bashbug - report a bug in bash

SYNOPSIS

       bashbug [--version] [--help] [email-address]

DESCRIPTION

       bashbug	is  a shell script to help the user compose and mail bug reports concerning bash in a standard format.	bashbug invokes the editor
       specified by the environment variable EDITOR on a temporary copy of the bug report format outline. The user must fill  in  the  appropriate
       fields  and  exit  the  editor.	 bashbug  then	mails the completed report to bug-bash@gnu.org, or email-address.  If the report cannot be
       mailed, it is saved in the file dead.bashbug in the invoking user's home directory.

       The bug report format outline consists of several sections.  The first section provides information about the  machine,	operating  system,
       the  bash  version, and the compilation environment.  The second section should be filled in with a description of the bug.  The third sec-
       tion should be a description of how to reproduce the bug.  The optional fourth section is for a proposed fix.  Fixes are encouraged.

ENVIRONMENT

       bashbug will utilize the following environment variables if they exist:

       EDITOR Specifies the preferred editor. If EDITOR is not set, bashbug defaults to emacs.

       HOME   Directory in which the failed bug report is saved if the mail fails.

       TMPDIR Directory in which to create temporary files and directories.

SEE ALSO

       bash(1)

AUTHORS

       Brian Fox, Free Software Foundation
       bfox@gnu.org

       Chet Ramey, Case Western Reserve University
       chet@po.cwru.edu

GNU Bash-4.0							   1998 July 30 							BASHBUG(1)
All times are GMT -4. The time now is 03:13 AM.
Unix & Linux Forums Content Copyright 1993-2022. All Rights Reserved.
Privacy Policy