Login or Register to Ask a Question and Join Our Community

Sponsored Content
Full Discussion: Bash: How to use read with conditions & loops
Top Forums Shell Programming and Scripting Bash: How to use read with conditions & loops Post 302983595 by MadeInGermany on Thursday 13th of October 2016 03:18:29 PM
Old 10-13-2016
You need a trick that stuffs the result into the variable name that has been passed to the function as an argument.
Like Chubler_XL's
Code:
  printf -v "$1" "%s" "$REPLY"

Or with read:
Code:
fetchip() {
  until
    read -p "$1: "
    [[ "$REPLY" =~ ^[0-9]+\.[0-9]+\.[0-9]+\.[0-9]+$ ]] &&
    {
    IFS=. read ip1 ip2 ip3 ip4 <<< "$REPLY"
    [[ $ip1 -le 255 && $ip2 -le 255 && $ip3 -le 255 && $ip4 -le 255 ]]
    }
  do
    echo "Invalid $1 IP address - Please re-enter"
  done
  # Read the $REPLY into the given variable name
  read "$1" <<< "$REPLY"
}

For consistent file naming you best define a variable, like
Code:
iffile=interfaces.txt

and then use $iffile.
With sed you can append to a certain line number (or to a line with a certain content)
Code:
sed -i '
12a\
 address '$address'\
 network '$network'\
 netmask '$netmask'\
 broadcast '$broadcast'\
 gateway '$gateway'
' "$iffile"

If this is at the end of the file, the shell can simply append a multi-line string to the file:
Code:
echo "\
 address $address
 network $network
 netmask $netmask
 broadcast $broadcast
 gateway $gateway" >> "$iffile"

 

10 More Discussions You Might Find Interesting

1. Shell Programming and Scripting

if statement with two conditions -e, &&

Wow I'm so zoned out I don't even know if I posted this question up already (I couldn't find it in my book marks or in "yesterday's" post). My question is, I'm writing a korn script that does something like the following, but I don't yet completely understand the syntax. I need to check that... (16 Replies)
Discussion started by: yongho
16 Replies

2. Shell Programming and Scripting

scripting headache... loops & variables

Surely there's an easier way to do this, lets see if anyone knows! I am new to scripting so go easy on me! I have the following script and at the moment it doesn't work and I believe the problem is that I am using a while loop within a while loop. When I run the script using sh -x I can see... (6 Replies)
Discussion started by: StevePace
6 Replies

3. Shell Programming and Scripting

multiple conditions in if using && operator

VARIABLE="project" if && ] then echo "VARIABLE is not empty" fi this is not working what is wrong in the syntax?? (2 Replies)
Discussion started by: codeman007
2 Replies

4. Shell Programming and Scripting

Bash Script to Read & Write on different directories

Hi, root@server] df -h 121G 14G 101G 12% /home 147G 126G 14G 91% /backup We having our site files and images are storing in /backup/home/user/files/ through symbolic link created in /home directory pointing in /backup directory as following. root@server] cd /home... (1 Reply)
Discussion started by: mirfan
1 Replies

5. Shell Programming and Scripting

PHP read large string & split in multidimensional arrays & assign fieldnames & write into MYSQL

Hi, I hope the title does not scare people to look into this thread but it describes roughly what I'm trying to do. I need a solution in PHP. I'm a programming beginner, so it might be that the approach to solve this, might be easier to solve with an other approach of someone else, so if you... (0 Replies)
Discussion started by: lowmaster
0 Replies

6. UNIX for Dummies Questions & Answers

Faster than nested while read loops?

Hi experts, I just want to know if there is a better solution to my nested while read loops below: while read line; do while read line2; do while read line3; do echo "$line $line2 $line3" done < file3.txt done < file2.txt done < file1.txt >... (4 Replies)
Discussion started by: chstr_14
4 Replies

7. Shell Programming and Scripting

bash loops

hello i'm writing a script and I want to use a for loop inside a while loop as following: while read line; do echo $line for i in $vrm; do echo $i done done < './contacts' when i use just the while loop it prints the lines from file ./contacts just... (13 Replies)
Discussion started by: vlm
13 Replies

8. Shell Programming and Scripting

GNU & BSD Makefile Directives & Conditions Compatibility

Firstly, I would like to apologize if this is not the appropriate sub-forum to post about GNU/BSD makefile scripting. Though my code is in C++, because I am focusing on the makefile I thought it would go better in shell scripting. Please correct me if I am wrong. Secondly, I am not interested in... (0 Replies)
Discussion started by: AntumDeluge
0 Replies

9. Shell Programming and Scripting

[Bash] Read History function & Read Arrowkeys

Hi. How can I create a history function? (By "read" command or so) & How can I configure a read command so that the arrow keys are not displayed so funny? (^[[A) Thanks in advance. (4 Replies)
Discussion started by: sinnlosername
4 Replies

10. UNIX for Dummies Questions & Answers

Loops & Variable

I am using this code: for e in {1..14} do awk '{gsub(/^.*GGGGGG|TTTTT.*$/,"",$0)} 1' $e.1 > ${e}.2 done However, in the second loop instead of GGGGGG|TTTTT, I should use AAAAAA|CCCCCC. For third loop CCAAAA|CCCCAA, so on and so forth. Is there any way to accomplish this without writing... (20 Replies)
Discussion started by: Xterra
20 Replies

LEARN ABOUT CENTOS

bashbug

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 07:58 PM.
Unix & Linux Forums Content Copyright 1993-2022. All Rights Reserved.
Privacy Policy