如何在 Bash 中写入二进制数据
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How to write binary data in Bash
提问by Jeevansai Jinne
Let us say there is a variable in bash script with value "001" how can i write this binary data into a file as bits (as "001" not "1") echo writes it as string but i want to write in bits.
假设 bash 脚本中有一个值为“001”的变量，我如何将此二进制数据作为位（如“001”而不是“1”）写入文件中，echo 将其写入为字符串，但我想以位写入。
回答by that other guy
You can write arbitrary bytes in hex or octal with:
您可以使用十六进制或八进制写入任意字节：
printf '\x03' > file # Hex
printf 'printf '%o\n' "$((2#00000011))"
3' > file # Octal
If you have binary, it's a bit tricker, but you can turn it into octal with:
如果你有二进制，它有点棘手，但你可以把它变成八进制：
binary=00000011
printf "\$(printf '%o' "$((2#$binary))")" > file
which of course can be nested in the above:
这当然可以嵌套在上面：
printf "%b" "2"
printf "%b" "\x0a"
Note that this only works with up to 8 bits. If you want to write longer values, you have to split it up into groups of 8.
请注意，这只适用于最多 8 位。如果你想写更长的值，你必须把它分成 8 个一组。
回答by jm666
Just use the %bin the printf:
只需%b在 printf 中使用：
printf "%b" "\x0a" | od -bc
%b - Print the associated argument while interpreting backslash escapes in there
%b - 在解释反斜杠转义时打印相关参数
so, above both prints binary value for the decimal 10.
所以，上面都打印十进制的二进制值10。
0000000 012
\n
output
输出
printf "%b" "\xa\n" | od -bc
0000000 012 012 012
\n \n \n
you can even mix
你甚至可以混合
# Write 32 bits 5 times to a file
for i in {1..5}
do
printf '\x12\x34\xAC\xCD' >> binaryfile.bin
done
回答by Xofo
Most often you want to write a pattern (for instance a 32 bit pattern).
大多数情况下，您想编写一个模式（例如 32 位模式）。
for i in {1..255}
do
hx=$( printf "%x" $i )
output="\x$hx\x00\x00\x00"
printf "%b" $output >> binaryfile.bin
done
Another example:
另一个例子：
le16 () { # little endian 16 bit; 1st param: integer to 2nd param: file
v=`awk -v n= 'BEGIN{printf "%04X", n;}'`
echo -n -e "\x${v:2:2}\x${v:0:2}" >>
}
le32 () { # 32 bit version
v=`awk -v n= 'BEGIN{printf "%08X", n;}'`
echo -n -e "\x${v:6:2}\x${v:4:2}\x${v:2:2}\x${v:0:2}" >>
}
回答by Hal Sampson
A couple of more general functions to output integers to a file:
几个将整数输出到文件的更通用的函数：
VALUE="3F"
INPUT_BASE=16
OUTPUT_BASE=2
printf "%b\n" $(bc <<< "ibase=$INPUT_BASE; obase=$OUTPUT_BASE; $VALUE")
回答by Sam
Using bc(in CentOS 7.4):
使用bc（在 CentOS 7.4 中）：
VALUE="3F"
INPUT_BASE=16
OUTPUT_BASE=2
printf "%16b\n" $(bc <<< "ibase=$INPUT_BASE; obase=$OUTPUT_BASE; $VALUE") | sed 's^ ^0^g'
RESULT: 111111
结果：111111
If leading zeros are needed then:
如果需要前导零，则：
##代码##RESULT: 0000000000111111
结果：0000000000111111
Note the use of 16 in the printf format; change value to limit leading-zero count
注意 printf 格式中 16 的使用；更改值以限制前导零计数
