bash脚本如何在不使用uudecode的情况下写出二进制文件？

Question

I've got a little puzzler here for the bash scripting experts... I have a bash script that needs to create a small (80 byte) binary file when it runs. The contents of the file need to be contained inside the script itself (ie I don't want to just package the file along with the script).

My script currently does it like this:

echo 'begin-base64 644 dummy.wav' > /tmp/dummy.uu
echo 'UklGRkgAAABXQVZFZm10IBAAAAADAAEAAHcBAADcBQAEACAAZmFjdAQAAAAAAAAAUEVBSxAAAAAB' >> /tmp/dummy.uu
echo 'AAAAQDYlTAAAAAAAAAAAZGF0YQAAAAA=' >> /tmp/dummy.uu
echo '====' >> /tmp/dummy.uu
uudecode -o /tmp/dummy.wav /tmp/dummy.uu
rm /tmp/dummy.uu

... after the above runs, I have my file /tmp/dummy.wav. But I just found out that the computer this script is to run on does not have uudecode installed (and I'm not allowed to install it), so I need to find some other way to create this file. Any ideas?

Answer 1

Some installers do something similar to this:

#!/bin/bash
tail -n +4 $0 | tar xvzf -
exit
<tgz file appended here><newline>

Answer 2

If the target computer has perl available:

perl -ne 'print unpack("u",$_)' > dummy.wav <<EOD
M4DE&1D@```!7059%9FUT(!`````#``$``'<!``#<!0`$`"``9F%C=`0`````
C````4$5!2Q`````!````0#8E3```````````9&%T80``````
EOD

That's using the non-base64 format you get from just doing uuencode dummy.wav < dummy.wav on your original computer.

Failing that, you can always do this:

echo -ne '\x52\x49\x46\x46\x48\x00\x00\x00'  > dummy.wav
echo -ne '\x57\x41\x56\x45\x66\x6d\x74\x20' >> dummy.wav
echo -ne '\x10\x00\x00\x00\x03\x00\x01\x00' >> dummy.wav
echo -ne '\x00\x77\x01\x00\x00\xdc\x05\x00' >> dummy.wav
echo -ne '\x04\x00\x20\x00\x66\x61\x63\x74' >> dummy.wav
echo -ne '\x04\x00\x00\x00\x00\x00\x00\x00' >> dummy.wav
echo -ne '\x50\x45\x41\x4b\x10\x00\x00\x00' >> dummy.wav
echo -ne '\x01\x00\x00\x00\x40\x36\x25\x4c' >> dummy.wav
echo -ne '\x00\x00\x00\x00\x00\x00\x00\x00' >> dummy.wav
echo -ne '\x64\x61\x74\x61\x00\x00\x00\x00' >> dummy.wav

This little bit of bash was generated with:

$ hexdump -e '"echo -ne '\''" 8/1 "x%02x" "'\'' >> dummy.wav\n"' dummy.wav | sed 's;x;\\x;g;1s/>/ /'

Edited to add: As pointed out in a reply here, something like this is also a possibility:

xargs -d'\n' -n1 echo -ne > dummy.wav <<EOD
\x52\x49\x46\x46\x48\x00\x00\x00\x57\x41\x56\x45\x66\x6d\x74\x20
\x10\x00\x00\x00\x03\x00\x01\x00\x00\x77\x01\x00\x00\xdc\x05\x00
\x04\x00\x20\x00\x66\x61\x63\x74\x04\x00\x00\x00\x00\x00\x00\x00
\x50\x45\x41\x4b\x10\x00\x00\x00\x01\x00\x00\x00\x40\x36\x25\x4c
\x00\x00\x00\x00\x00\x00\x00\x00\x64\x61\x74\x61\x00\x00\x00\x00
EOD

(the -d argument is important to turn off xargs 's own backslash processing)

You can also turn the 8/1 in my hexdump command into 80/1 and have a single long echo line.

Answer 3

#!/bin/bash

# Define usage help
usage () {
    echo -e "USAGE:\n\t$0 <file to create> <dir to tar> <name of script or command to run>\n"
    exit 0
}

# check commandline arguments
if [ "$1" = "-h" ]; then usage; fi
if [ -z $1 ]; then usage; fi
if [ -z $2 ]; then usage; fi
if [ -z $3 ]; then usage; fi

# test for the directory and if it exists, create the bin file using tar
if [ -d "$2" ]; then
    cat >$1<<EOF
#!/bin/sh -e
sed -e '1,/^exit$/d' "\$0" | tar xzf - && "./$2/$3"
exit
EOF
    tar czf - $2 >> $1
else
    echo "$2 does not exist, aborting!"
    exit 1
fi

# make the new file executable and exit
chmod +x $1
exit 0

Answer 4

我会使用base64编码，因为它似乎是uu编码的一般替代品，并且操作的原理非常相似。

Answer 5

Put an exit at the end of your script, append the file to the end of the script, and use tail -c 80 to get at the contents. This will work as long as you don't need to worry about newline conversion issues.

Answer 6

This is another example to decode radix 64 formatted data, it runs slow, but it is functional.

#!/bin/bash
exec<$0
while read line ; do if [ "$line" = "#payload" ] ; then break; fi; done
r64='ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/'
i=0; while [ $i -lt 256 ] ; do tab[$i]=-1 ; let i=$i+1 ;done
i=0; while [ $i -lt 64 ] ; do tab[`printf "%d" "'${r64:$i:1}"`]=$i ; let i=$i+1; done
bi=0
while read -n 1 x
do
 in=${tab[`printf "%d" "'$x"`]}
 if [ $in -ge 0 ]; then case $bi in
  0 ) out=$(($in<<2)); bi=6 ;;
  2 ) out=$(($out|$in)); printf \\$(printf '%03o' $(($out&255)) ); bi=0 ;;
  4 ) out=$(($out+($in>>2))); printf \\$(printf '%03o' $(($out&255)) );
  bi=0; out=$(($in<<6)); bi=2 ;;
  * ) out=$(($out+($in>>4))); printf \\$(printf '%03o' $(($out&255)) );
  bi=0; out=$(($in<<4)); bi=4 ;;
  esac fi
done
exit
#payload
dnZ2dnZ2dnZ2dnZ2dnZ2dnZ2XmAgICAte3Z2dnZ2dnZ2dnZ2dnZ2dgp2dnZ2dnZ2dnZ2dnZ2dnZ2PiAg
ICAgIC4gLXZ2dnZ2dnZ2dnZ2dnZ2CnZ2dnZ2dnZ2dnZ2dnZ2dn0gICAgICAgPT4gLXZ2dnZ2dnZ2dnZ2
dnYKdnZ2dnZJdnZJdnZJdnZJOyAgICAgICAtICAgPXZJdkl2dkl2dkl2dgp2dnZ2SXZ2dnZ2dnZ2dnZg
ICAgICAgICAgICAgbnZ2dnZJdnZ2dnZ2CnZ2dnZ2dnZ2SXZJdnZJdiAgIC4gICAgICwgICA8dnZ2SXZ2
dkl2dkkKdnZ2SXZ2SXZ2dnZ2SXZJIF9zOyAgX3VvLyAgID12dnZ2dnZ2dnZJdgp2dnZ2dkl2dnZJdnZ2
dnYgdyRtICBtQCRtICAgPXZ2dnZJdnZJdnZ2CnZ2dnZJdnZ2dnZ2dkl2SSBmPTQuO1cgYFE7ICA9dnZ2
dnZ2dnZ2dnYKdnZ2SXZ2dnZJdnZJdnZ2IHQtM3MlJiAgbWAgID12dnZ2SXZJdnZJdgp2dnZ2dnZ2SXZ2
dnZ2dnYgXWlvWjZYYXVQICAgPXZ2dnZ2dnZ2SXZ2CnZ2dkl2dkl2dnZJdnZJdi4pbVojWlojWlMgICAu
dnZ2SXZJdnZ2dnYKdnZ2dnZ2dnZ2dnZ2SXZ2OjNYWlpaI1pTWCAgICB7dnZ2dnZ2dkl2dgp2dnZ2SXZ2
SXZ2SXZ2dnY7PFNYWlhTZFhuIC5pLj12dnZJdnZJdnZ2CnZ2dkl2dnZ2dkl2dnZ2dmBdJVhYWlhubW0+
IC1gIHZ2dnZ2dnZ2dnYKdnZ2dnZ2SXZ2dnZ2SXYlIGptdklud1FXUW0gICAgPHZ2SXZ2SXZ2SQp2dnZJ
dnZ2dkl2dkl2dmAuUVFvWG1tUVFRUWMgICAge0l2dnZ2dnZ2CnZ2dnZ2dkl2dnZ2dnYrIGpRV1FtV1FR
UVFRayAgICAtdnZ2dkl2dkkKdnZ2dkl2dnZ2SXZJPiBfUVFRUVFRUVFRUVFRLiAgICA9dkl2dnZ2dgp2
dnZJdnZ2SXZ2dmwgIF1RUVFRV1FRUVdXOCRMICAgICA8dnZ2SXZ2CnZ2dnZ2dnZ2dnZ2OyAgbm1RUVFt
UVFRbXdvb20gLiAgIC1JdnZ2dnYKdnZ2SXZ2SXZ2SX0gID1RV1FRUVFRUVFRUVFtMlsgLSAgID12dkl2
dgp2dnZ2dnZ2dkl2Oy4gZFFRUVFRUVFRUVFRUVFRcSAgLiAgIEl2dnZ2CnZ2dnZJdkl2dnZgLjxRUVFR
UVFRUVFRUVFRUVdRKC4uLiAgPEl2dnYKdnZ2SXZ2dnZ2PiAgZFFRUVFRUVFRUVFRUVFRUVFbICAuICAg
dnZ2SQp2dnZ2dnZ2dnYnIC5RUVFRUVFRUVFRUVFRUVFRUWsgIC4gICB7dnZ2CnZ2dkl2dkl2PiAuXVFR
UVFRV1dXUVFRUVFRUVFRbSAgICAgIClsdnYKdnZ2dnZ2dnZgIDpqUVFRUVEjUVdRUVFRUVFRUVFXICAu
ICAgOnZ2SQp2dnZ2SXZ2bCAgOmpXUVFRUUVXV1FRUVFRV1FRUVcgIGAgICA6dnZ2CnZ2dkl2dnZJLl86
alFRUVFRRVdRUVFRUVFRUVFRVyAuIC4uID12dnYKdnZ2dnZ2dnZkIzYvUVdRUVFFUVFRUVFRUVFRV1dM
LiAgIDogKXZ2dgp2dnZJdnZJMyNaWkwtJFFRUVFRV1FRUVFRUVFCWiNgICAgLmRvdnZ2CnZ2dnZ2SXZa
IyMjWj4tNFFRUVdRUVFRUVFRUUVaay4gICBqWlh2dnYKdnZ2dndvbVgjWiNaIy4gNFFRUVFRUVFRUVdX
MVpYc189dVhaaHZ2dgp2dnZaWiNaI1VVWiNaTCAgXVFRUVFRUVFRUVdlWFpYcVhtWiNVenZ2CnZ2SVgj
I1ojWiMjWiNaLyAuUVFRUVFRUVFRVzEzI1paWlojWiMjb3YKdnZ2ZFVaIyNVWiMjVVVoX2FRUVFRUVFR
UVFQOlhaIyNVI1ojVVojaAp2dklkIyNaI1ojI1ojWlpaV1FRUVFRUVFXUCA9ZFojWiNaIyNaIyNaCnZ2
dlojWiMjVVVaI1ojWlpKUVFRUVFXUF4gIClYIyNaI1VVWiNVWjEKdnZ7WlojWlVaIyNaIyNaVXMtIT8i
fiAgICAgdlgjWiMjWiNaWF5sdgp2bCBZWFhYWFpaVVUjWlpaMS4gICAgICAgICB2WFojWiNaWCIgIDx2
CnZzICAtfiJJMVhYWFpaWm8xICAgICAgICAgIEluWFhaU31gICAgPHYKdnY7ICAgICAtLTwxMjIxbGAg
ICAgICAgICAgPElubjF9ICAgICB2SQp2dmwsICAgICAgICB+Kz5gICAgICAgICAgICAgfnwrfiAgICAu
JUl2CnZ2dnZpLiAgICAgICAgICAgIF9pc2ksICAgICAgICAgICAgX3ZJdnYKdnZ2dnZ2c19fXy4uLi5f
XyV2dnZ2SXZpLCxfLiAuLl9fPnZ2dnZ2dgp2dnZ2SXZ2dm52dnZ2dnZudnZ2dnZ2dnZubnZ2dnZ2dnZ2
dnZ2dnZ2Cg==

Answer 7

Just encode the binary data in base64 and do something like this:

#! /bin/bash

cat <<EOF | base64 -d > wherever-it-goes.bin
UtEOtUaZcUCrEJtPJrA34BH8Wdpxb1/DtfMo5syiE/h+moNyApEkg2ZwA2/jTDdfl4WijnNbMzvZ
RrF3i7X353AjmTjLBz1NcOOJJhRPYLJ4WQYONyYj/fAhnXQd+s4SHaNponOWKj1AAzdlJY1VLWaX
P8QBJQcn2FTL4pJ3N04=
EOF

Answer 8

From my point of view uuencode and uudecode are essential, but that's only my opinion. Without creating temporary files you could also do something like this (uudecode.sh):

#!/bin/bash
# --
# -- Uudecoding without using a regular temporary file
# --

# -- Create a named pipe:
mknod /tmp/.dummypipe p

# -- Starting uudecoding on that pipe in the background:
uudecode -o dummy.txt /tmp/.dummypipe &

# -- Push base64-uuencoded content into the named pipe:
cat <<END_DUMMY > /tmp/.dummypipe
begin-base64 644 dummy.txt
VGhpcyBpcyB0aGUgdXVkZWNvZGVkIHRleHQuCg==
====
END_DUMMY

# -- Remove the named pipe
rm /tmp/.dummypipe