[scripts,egs] Fix shebangs on bash scripts to #!/usr/bin/env bash, for portability (#3881)

Author: esdeboer

egs/aidatatang_200zh/s5/local/chain/compare_wer.sh

@@ -1,4 +1,4 @@
-#!/bin/bash
+#!/usr/bin/env bash
 # Copyright 2018  Emotech LTD (Author: Xuechen Liu)
 
 # compare wer between diff. models in aidatatang_200zh chain directory

egs/aidatatang_200zh/s5/local/chain/tuning/run_tdnn_1a.sh

@@ -1,4 +1,4 @@
-#!/bin/bash
+#!/usr/bin/env bash
 
 # This script is based on run_tdnn_7h.sh in swbd chain recipe.
 

egs/aidatatang_200zh/s5/local/chain/tuning/run_tdnn_2a.sh

@@ -1,4 +1,4 @@
-#!/bin/bash
+#!/usr/bin/env bash
 
 # This script is based on run_tdnn_1a.sh.
 # This setup used online pitch to train the neural network.

egs/aidatatang_200zh/s5/local/data_prep.sh

@@ -1,4 +1,4 @@
-#!/bin/bash
+#!/usr/bin/env bash
 
 # Copyright 2017 Xingyu Na
 # Apache 2.0

egs/aidatatang_200zh/s5/local/download_and_untar.sh

@@ -1,4 +1,4 @@
-#!/bin/bash
+#!/usr/bin/env bash
 
 # Copyright   2014  Johns Hopkins University (author: Daniel Povey)
 #             2017  Xingyu Na

egs/aidatatang_200zh/s5/local/format_data.sh

@@ -1,4 +1,4 @@
-#!/bin/bash
+#!/usr/bin/env bash
 #
 
 . ./path.sh

egs/aidatatang_200zh/s5/local/nnet3/compare_wer.sh

@@ -1,4 +1,4 @@
-#!/bin/bash
+#!/usr/bin/env bash
 # Copyright 2018  Emotech LTD (Author: Xuechen Liu)
 
 # compare wer between diff. models in aidatatang_200zh nnet3 directory

egs/aidatatang_200zh/s5/local/nnet3/run_ivector_common.sh

@@ -1,4 +1,4 @@
-#!/bin/bash
+#!/usr/bin/env bash
 
 set -euo pipefail
 

egs/aidatatang_200zh/s5/local/nnet3/tuning/run_tdnn.sh

@@ -1,4 +1,4 @@
-#!/bin/bash
+#!/usr/bin/env bash
 
 # This script is based on aishell/s5/local/nnet3/tuning/run_tdnn_1a.sh
 

egs/aidatatang_200zh/s5/local/prepare_dict.sh

@@ -1,4 +1,4 @@
-#!/bin/bash
+#!/usr/bin/env bash
 #Copyright 2016 LeSpeech (Author: Xingyu Na)
 
 # prepare dictionary for aidatatang