Return to Answer

0. Don't reinvent the wheel

   There could already exist some tool for doing what you need.

1. Check your history files

   grep mycommand .*history
   

2. Don't use command line arguments or environment variables to store sensible datas (like password)!

   Always use files or fd (file descriptors)! Try

   ps axefwww
   

   to read all command lines and environment, currently running on your host

0. Don't reinvent the wheel

   There could already exist some tool for doing what you need.

1. Check your history files

   grep mycommand .*history
   

2. Don't use command line arguments or environment variables to store sensitive data (like passwords)!

   Always use files or fd (file descriptors)! Try

   ps axefwww
   

   to read all command lines and environment, currently running on your host

0. Don't reinvent the wheel

   There could already exist some tool for doing what you need.

1. Check your history files

   grep mycommand .*history
   

2. Don't use command line arguments or environment variables to store sensible datas (like password)!

   Always use fd (file descriptors)! Try

   ps axefwww
   

   to read all command lines and environment, currently running on your host

#!/bin/sh

umask 077
TEMPDIR=$(mktemp -d -p $HOME .secretXXXXXXXX)
trap "rm -fR $TEMPDIR;exit" 0 1 2 3 6 9 15
[ "$TEMPDIR" ] || exit 1
cd $TEMPDIR || exit 1

ostty=$(stty -g)
stty -echo

printf "\nEnter password: "
head -n1 >pass1

printf "\nRe-enter password: "
head -n1 >pass2

stty $ostty
echo

chk1=$(sha1sum <pass1)
chk2=$(sha1sum <pass2)

[ "$chk1" = "$chk2" ] || {
    echo "password doesn't match"
    exit 1
}

openssl DoSomeThingWith -passin file:pass1

0. Don't reinvent the wheel

   There could already exist some tool for doing what you need.

1. Check your history files

   grep mycommand .*history
   

2. Don't use command line arguments or environment variables to store sensible datas (like password)!

   Always use files or fd (file descriptors)! Try

   ps axefwww
   

   to read all command lines and environment, currently running on your host

#!/bin/sh

umask 077
TEMPDIR=$(mktemp -d -p "$HOME" .secretXXXXXXXX)
trap "rm -fR '$TEMPDIR';exit" 0 1 2 3 6 9 15
[ "$TEMPDIR" ] || exit 1
cd "$TEMPDIR" || exit 1

ostty=$(stty -g)
stty -echo

printf "\nEnter password: "
head -n1 >pass1

printf "\nRe-enter password: "
head -n1 >pass2

stty $ostty
echo

chk1=$(sha1sum <pass1)
chk2=$(sha1sum <pass2)

[ "$chk1" = "$chk2" ] || {
    echo "password doesn't match"
    exit 1
}

openssl DoSomeThingWith -passin file:pass1

Introduction

Little sample

#!/bin/sh

umask 077
TEMPDIR=$(mktemp -d -p $HOME .secretXXXXXXXX)
trap "rm -fR $TEMPDIR;exit" 0 1 2 3 6 9 15
[ "$TEMPDIR" ] || exit 1
cd $TEMPDIR || exit 1

ostty=$(stty -g)
stty -echo

printf "\nEnter password: "
head -n1 >pass1

printf "\nRe-enter password: "
head -n1 >pass2

stty $ostty
echo

chk1=$(sha1sum <pass1)
chk2=$(sha1sum <pass2)

[ "$chk1" = "$chk2" ] || {
    echo "password doesn't match"
    exit 1
}

openssl DoSomeThingWith -passin file:pass1