device_to_edit=/dev/sdb; string_to_edit="quiet splas\x68"; new_string="persistent  "; block_size=512; ed_count=0; to_end=""; if [ ! ${#string_to_edit} -eq ${#new_string} ]; then echo -e "\n Suspect a danger as strings lengths not same"; elif [ $block_size -lt ${#new_string} ]; then echo -e "\n\ Suspect a danger as block size too small for string length"; elif file_size=$(lsblk -b --output PATH,SIZE | grep "$device_to_edit " | sed -E 's/.* ([0-9]{1,})/\1/'); [ $((file_size/1024/1024/1024)) -gt 20 ]; then echo -e "\n Suspect a danger as device size is large"; else while [ -z $to_end ]; do offset_to_edit=$(sudo grep --only-matching --byte-offset --max-count=1 --text --perl-regexp "$string_to_edit" $device_to_edit | awk --field-separator ":" '{ FS = "0" ; print $1 ; exit }'); if [ -z "$offset_to_edit" ]; then echo -e "\n end of file is reached" ; to_end="yes" ; else block_to_edit=$(($offset_to_edit/$block_size)) ; sudo dd if=/$device_to_edit count=2 skip=$block_to_edit bs=$block_size | sed "s/$string_to_edit/$new_string/" | sudo dd conv=notrunc of=$device_to_edit count=2 seek=$block_to_edit bs=$block_size; echo "blocks $block_to_edit and next edited (blocks start with 0)"; ((ed_count++)) ; fi ; done ; echo -e "\n$ed_count editions made"; fi

date; device_to_edit=/dev/sdb; string_to_edit="quiet splash"; new_string="persistent  "; block_size=512; ed_count=0; to_end=""; if [ ! ${#string_to_edit} -eq ${#new_string} ]; then echo -e "\n Suspect a danger as strings lengths not same"; elif [ $block_size -lt ${#new_string} ]; then echo -e "\n\ Suspect a danger as block size too small for string length"; elif file_size=$(lsblk -b --output PATH,SIZE | grep "$device_to_edit " | sed -E 's/.* ([0-9]{1,})/\1/'); [ $((file_size/1024/1024/1024)) -gt 20 ]; then echo -e "\n Suspect a danger as device size is large"; else sudo grep --only-matching --byte-offset --text --perl-regexp "$string_to_edit" $device_to_edit | awk --field-separator ":" '{ FS = ":" ; print $1 }' | { IFS=备注：通过读取man bash、man awk、man sed、info '(coreutils) dd invocation'、help read可以理解脚本参数和语法的含义。为什么管道中所需的(list) / { list; }在https://stackoverflow.com/questions/2746553/read-values-into-a-shell-variable-from-a-pipe中得到解释(“管道可能产生一个子subshell，其中环境是由值而不是引用继承的”)，在字符串从一个块开始并在下一个块中结束的情况下，需要使用两个块。这些光盘包括三个安全检查:原始字符串和替换字符串的长度相同，块大小足够大，设备大小不大于20 be (防止主驱动器意外编辑，需要编辑更大的闪存，代码为$((file_size/1024/1024/1024)) -gt 20)。脚本中有一些冗余，例如FS = ":" ; in awk，由于某些原因，字段分隔符没有像我预期的那样工作，我不得不添加--field-separator ":"，在grep --perl-regexp中也需要使用十六进制(例如\xaa值)，但是这个编辑没有它们。\n' read -d '' -a offsets_to_edit ; for offset in ${offsets_to_edit[@]}; do block_to_edit=$(($offset/$block_size)) ; sudo dd if=/$device_to_edit count=2 skip=$block_to_edit bs=$block_size | sed "s/$string_to_edit/$new_string/" | sudo dd conv=notrunc of=$device_to_edit count=2 seek=$block_to_edit bs=$block_size; echo "blocks $block_to_edit and next edited (blocks start with 0)"; ((ed_count++)); done; echo -e "\n$ed_count editions made"; } ; fi; date