创建脚本test.sh：@H_301_7@

#!/usr/bin/env bash

sleep 1
echo 'echo "executed overwritten"' >> "$0"   # append to self
sleep 1
echo 'executed original'

并执行它：@H_301_7@

$bash --version
GNU bash,version 4.2.24(1)-release (i686-pc-linux-gnu)
Copyright (C) 2011 Free Software Foundation,Inc.
License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>

This is free software; you are free to change and redistribute it.
There is NO WARRANTY,to the extent permitted by law.
$chmod +x test.sh 
$./test.sh 
executed original
executed overwritten
$

请注意,bash继续阅读修改后的文件.当文件更改时,它会保留其文件中的当前位置(以字节为单位).@H_301_7@

作为示范,脚本@H_301_7@

#!/usr/bin/env bash

sleep 1
dd if=/dev/urandom bs=1024 count=1 of="$0" &>/dev/null   # overwrite self
sleep 1
echo 'executed original'

给出输出@H_301_7@

$./test.sh 
./test.sh: line 6: Syntax error near unexpected token `$'\311\262\203''
./test.sh: line 6: `��z�eп9)�v��▒y�a��44'{�d��4\:�A����˷���&�$�����l�
@(ɲ��4��OϹI�n>��7��P�M�a��X.�S�a���V�m�~O<��{}������J��$��TOtRd��Nw�&��B�Dz�▒��-��<`�P<?N��▒rT�Jq�L����JY�*hz���M�����i�⫣��S+�����\��c���m�NKV�8|��xvX}�׉V����PTd䊄�9��7���|��/��X��
                                                                                                       ��0¤k��_�R���e�*���(qu:UUɭp/j��n��bŇ_�UR?3▒�▒�%Rn�|DE$8�QbaK)A�{ ��O>9��A�����lt�����g)s��O��M��@���w��|�����N��,W'

请注意,它试图执行随机乱码.@H_301_7@

(这是Ubuntu 12.04.行为可能因其他shell而异)@H_301_7@