Question

我想要完成的事情：我有一个文件，我需要从某个位置复制某些字节并将它们附加到该文件的给定位置的文件中。

我在想这样的事情：

xxd -s $startOffset -l $numBytes inFile | dd of=fileToModify seek=$location conv=notrunc

我也有这个，但它只适用于附加在文件的开头。

read -p "Enter target file :> " targetFile
read -p "Enter source file to append at the end of target file :> " inputFile
dd if=$inputFile of=$targetFile oflag=append conv=notrunc

提前谢谢！

Answer 1

试试这个：

# copy certain bytes from a certain location 
file=$1
certainlocation=$2
certainbytes=$3
# Append them to a file at a given location of that file
givenlocation=$4

dd if=$file of=$file iflag=skip_bytes oflag=seek_bytes,append conv=notrunc skip=$certainlocation seek=$givenlocation count=1 bs=$certainbytes

用法：

> printf "1\n2\n3\n4\n" > /tmp/1; ./1.sh /tmp/1 4 2 2; cat /tmp/1;
1+0 records in
1+0 records out
2 bytes copied, 0.000378992 s, 5.3 kB/s
1
2
3
4
3

Answer 2

{
  dd if=inFile iflag=count_bytes count="$targetByteLocation" status=none
  cat -- "$fileToAppend"
  dd if=inFile iflag=skip_bytes skip="$targetByteLocation" status=none
} >outFile

Answer 3

第一个文件的内容

$ cat first
fskasfdklsgdfksdjhgf sadjfsdjfhf
dsfghkasdfg sadfhsdfh hskdjfksdfgkfg
jhfksjdafhksdjfh


ksdjhfsdjfh

sceond文件的内容

$ cat second
jfhasjdhfjskdhf dshfjsdfh3821349832749832]
87348732642364
]yfisdfhshf936494
sdfisdfsdfsa;dlf
9346934623984

shell脚本的内容

$ cat cppaste.sh
dd if=$1 of=$2 bs=1 count=$3 status=noxfer
dd if=$4 of=$2 bs=1 seek=$3 status=noxfer
finsize=$(stat -c%s $2)
dd if=$1 of=$2 bs=1 skip=$3 seek=$finsize oflag=append status=noxfer

使用适当的参数执行shell脚本

$ bash cppaste.sh first  third 10 second
10+0 records in
10+0 records out
107+0 records in
107+0 records out
92+0 records in
92+0 records out

结果文件的内容

$ cat third
fskasfdklsjfhasjdhfjskdhf dshfjsdfh3821349832749832]
87348732642364
]yfisdfhshf936494
sdfisdfsdfsa;dlf
9346934623984
gdfksdjhgf sadjfsdjfhf
dsfghkasdfg sadfhsdfh hskdjfksdfgkfg
jhfksjdafhksdjfh


ksdjhfsdjfh

bash脚本：将输入文件中的字节附加到给定字节偏移位置的预先存在的文件

3 个答案: