Login or Register to Ask a Question and Join Our Community

Sponsored Content
Full Discussion: Bash script to accept password and replace characters with * as they are typed
Top Forums Shell Programming and Scripting Bash script to accept password and replace characters with * as they are typed Post 302559840 by gary_w on Wednesday 28th of September 2011 09:46:12 AM
Old 09-28-2011
For the sake of argument, here is an example ksh script called "getpw" that I have in my bag of tricks. I did not write this, but saw it somewhere and saved it. My apologies to the author. Perhaps it can be adapted to bash, or at least studied to learn some new tricks :-)
Code:
#! /usr/bin/ksh
exec 4>/dev/tty
function getpass
{
  typeset prompt=$1
  typeset backspace=$(echo  \\b\\c)
  typeset enter=$(echo \\r\\c)
  typeset savesetting=$(stty -g)
  typeset keystroke password n i reading result
  n=0
  echo "${prompt}"\\c >&4
  stty -echo -icrnl -icanon min 1 time 0
  reading=1

  while ((reading)) ; do
    keystroke=$(dd bs=1 count=1 2>/dev/null)
    case $keystroke in
          $enter) reading=0
                  ;;
      $backspace) if ((n)) ; then
                    echo "${backspace} ${backspace}"\\c >&4
                    ((n=n-1))
                  fi
                  ;;
               *) echo \*\\c >&4
                  data[n]=$keystroke
                  ((n=n+1))
                  ;;
    esac
  done

  stty "$savesetting"
  echo >&4
  result=""
  i=0

  while ((i<n)) ; do
    result="${result}${data[i]}"
    ((i=i+1))
  done

  echo $result
  return 0
}

final=$(getpass "password: ")
echo the password is $final
exit 0

Last edited by gary_w; 09-28-2011 at 11:31 AM.. Reason: reformatted for readability
These 2 Users Gave Thanks to gary_w For This Post:
Chubler_XL vgersh99
 

9 More Discussions You Might Find Interesting

1. Shell Programming and Scripting

how to set a variable to accept alpha-numeric characters?

I am working on a shell program that needs to accept alpha-numeric input (i.e., P00375); when I use a simple 'read' statement to read in the input (i.e., read LOG), I receive the message "p00375: bad number". How must I adjust my input statement to accept alpha-numerics? Thanks! Brent (3 Replies)
Discussion started by: bcaunt
3 Replies

2. UNIX for Dummies Questions & Answers

ASCII character to accept logon password

Hey all, Just found your forum...Looks super rich with info! Can't wait to get through it all. I am currently writing a web app in .net that telnets into a unix server (require uid + passwd), runs a command, and returns that output to be displayed on the web page. I have gotten through the... (8 Replies)
Discussion started by: gord
8 Replies

3. Shell Programming and Scripting

Bash script - stripping away characters that can't be used in filenames

I want to create a temp file which is named based on a search string. The search string may contain spaces or characters that aren't supposed to be used in filenames so I want to strip those out. My thought was to use 'tr' with but the result is the opposite of what I want: $ echo "test... (5 Replies)
Discussion started by: mglenney
5 Replies

4. Shell Programming and Scripting

Bash: using SED, trying to replace some characters except first or last line

Hi, I require to replace 2 items: 1. replace start of all lines in a file with ' except the first line 2. replace end of all lines in a file with '||chr( except last line I am able to do the entire file using sed -e s/^/\'/g -e s/$/\'\|\|chr\(/g "$file" > newfile.txt but am not yet able... (0 Replies)
Discussion started by: Chella15
0 Replies

5. UNIX for Dummies Questions & Answers

Bash: using SED, trying to replace some characters except first or last line

Hi, I require to replace 2 items: 1. replace start of all lines in a file with ' except the first line 2. replace end of all lines in a file with '||chr( except last line I am able to do the entire file using sed -e s/^/\'/g -e s/$/\'\|\|chr\(/g "$file" > newfile.txt but am not yet... (3 Replies)
Discussion started by: Chella15
3 Replies

6. Shell Programming and Scripting

bash script using scp (pw typed by hand) followed by removal of files

Hello, I tried to write a bash script (code is below) that does scp files that contain a certain string, and that subsequently deletes only those files that have been copied (in my case new files are created every second so it is important to only delete those that have been copied). The key is... (0 Replies)
Discussion started by: kjartan
0 Replies

7. Shell Programming and Scripting

Make a password protected bash script resist/refuse “bash -x” when the password is given

I want to give my long scripts to customer. The customer must not be able to read the scripts even if he has the password. The following command locks and unlocks the script but the set +x is simply ignored. The code: read -p 'Script: ' S && C=$S.crypt H='eval "$((dd if=$0 bs=1 skip=//|gpg... (7 Replies)
Discussion started by: frad
7 Replies

8. How to Post in the The UNIX and Linux Forums

How to replace value of password tag in xml with blanks when special characters are there?

Hi All, I am trying to replace the values inside <password> tag in an xml file but it doesn't replace certain passwords: For eg: Server/home/sperinc>cat TextXML.txt <appIds> <entry name="AccountXref"> <type id="ldap"> <realm>nam</realm> ... (7 Replies)
Discussion started by: saroopkris85
7 Replies

9. Shell Programming and Scripting

Bash script for password changes help

I am super new to scripting and I am trying to create a bash script that is interactive that will change other user passwords as well as a few other thing (ie. change SMB pw, see pw expiration,lock/unlock user). I have started it by making it check to see if the username entered is in the... (2 Replies)
Discussion started by: thumbelina
2 Replies

LEARN ABOUT DEBIAN

ppmtosixel

ppmtosixel(1)						      General Commands Manual						     ppmtosixel(1)

NAME

       ppmtosixel - convert a portable pixmap into DEC sixel format

SYNOPSIS

       ppmtosixel [-raw] [-margin] [ppmfile]

DESCRIPTION

       Reads  a  portable  pixmap  as input.  Produces sixel commands (SIX) as output.	The output is formatted for color printing, e.g. for a DEC
       LJ250 color inkjet printer.

       If RGB values from the PPM file do not have maxval=100, the RGB values are rescaled.  A printer control header and a color assignment table
       begin the SIX file.  Image data is written in a compressed format by default.  A printer control footer ends the image file.

OPTIONS

       -raw   If  specified,  each  pixel  will  be explicitly described in the image file.  If -raw is not specified, output will default to com-
	      pressed format in which identical adjacent pixels are replaced by "repeat pixel" commands.  A raw file is often an order	of  magni-
	      tude larger than a compressed file and prints much slower.

       -margin
	      If  -margin  is not specified, the image will be start at the left margin (of the window, paper, or whatever).  If -margin is speci-
	      fied, a 1.5 inch left margin will offset the image.

PRINTING

       Generally, sixel files must reach the printer unfiltered.  Use the lpr -x option or cat filename > /dev/tty0?.

BUGS

       Upon rescaling, truncation of the least significant bits of RGB values may result in poor color conversion.  If the original PPM maxval was
       greater	than  100,  rescaling  also reduces the image depth.  While the actual RGB values from the ppm file are more or less retained, the
       color palette of the LJ250 may not match the colors on your screen.  This seems to be a printer limitation.

SEE ALSO

       ppm(5)

AUTHOR

       Copyright (C) 1991 by Rick Vinci.

								   26 April 1991						     ppmtosixel(1)
All times are GMT -4. The time now is 09:27 AM.
Unix & Linux Forums Content Copyright 1993-2022. All Rights Reserved.
Privacy Policy