Bash: Use raw binary in variable as executable?
up vote
2
down vote
favorite
1
I'd like to create a variable containing binary data, then execute in a command. Example:
#!/bin/bash
var="$(cat /bin/sleep)"
"$var" 9999
linux bash shell ubuntu variable
asked Nov 17 at 23:59
user321517
202
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up vote
2
down vote
favorite
1
I'd like to create a variable containing binary data, then execute in a command. Example:
#!/bin/bash
var="$(cat /bin/sleep)"
"$var" 9999
linux bash shell ubuntu variable
asked Nov 17 at 23:59
user321517
202
New contributor
user321517 is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
add a comment |
up vote
2
down vote
favorite
1
up vote
2
down vote
favorite
1
1
I'd like to create a variable containing binary data, then execute in a command. Example:
#!/bin/bash
var="$(cat /bin/sleep)"
"$var" 9999
linux bash shell ubuntu variable
asked Nov 17 at 23:59
user321517
202
New contributor
user321517 is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
I'd like to create a variable containing binary data, then execute in a command. Example:
#!/bin/bash
var="$(cat /bin/sleep)"
"$var" 9999
linux bash shell ubuntu variable
linux bash shell ubuntu variable
asked Nov 17 at 23:59
user321517
202
New contributor
user321517 is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
asked Nov 17 at 23:59
user321517
202
New contributor
user321517 is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
asked Nov 17 at 23:59
user321517
202
New contributor
user321517 is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
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asked Nov 17 at 23:59
user321517
202
asked Nov 17 at 23:59
user321517
202
202
New contributor
user321517 is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
New contributor
user321517 is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
user321517 is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
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1 Answer
1
active
oldest
votes
up vote
3
down vote
accepted
You cannot execute a variable like that because:
- the kernel executes files,
- the shell can execute command lines stored in variables, but it cannot interpret binary data
- storing a binary file's contents in a variable will likely not work well, because null bytes may be present in the file (and you can't have null bytes in variables of most shells)
- even if you used process substitution to get a temporary file with the contents of that variable, process substitution file handles won't be executable
So you'll have to store the contents in a file, make that file executable, hope that nothing got missed because of a null bytes, and execute that file.
answered Nov 18 at 0:52
muru
35.1k581154
add a comment |
1 Answer
1
active
oldest
votes
1 Answer
1
active
oldest
votes
active
oldest
votes
active
oldest
votes
up vote
3
down vote
accepted
You cannot execute a variable like that because:
- the kernel executes files,
- the shell can execute command lines stored in variables, but it cannot interpret binary data
- storing a binary file's contents in a variable will likely not work well, because null bytes may be present in the file (and you can't have null bytes in variables of most shells)
- even if you used process substitution to get a temporary file with the contents of that variable, process substitution file handles won't be executable
So you'll have to store the contents in a file, make that file executable, hope that nothing got missed because of a null bytes, and execute that file.
answered Nov 18 at 0:52
muru
35.1k581154
add a comment |
up vote
3
down vote
accepted
You cannot execute a variable like that because:
- the kernel executes files,
- the shell can execute command lines stored in variables, but it cannot interpret binary data
- storing a binary file's contents in a variable will likely not work well, because null bytes may be present in the file (and you can't have null bytes in variables of most shells)
- even if you used process substitution to get a temporary file with the contents of that variable, process substitution file handles won't be executable
So you'll have to store the contents in a file, make that file executable, hope that nothing got missed because of a null bytes, and execute that file.
answered Nov 18 at 0:52
muru
35.1k581154
add a comment |
up vote
3
down vote
accepted
up vote
3
down vote
accepted
You cannot execute a variable like that because:
- the kernel executes files,
- the shell can execute command lines stored in variables, but it cannot interpret binary data
- storing a binary file's contents in a variable will likely not work well, because null bytes may be present in the file (and you can't have null bytes in variables of most shells)
- even if you used process substitution to get a temporary file with the contents of that variable, process substitution file handles won't be executable
So you'll have to store the contents in a file, make that file executable, hope that nothing got missed because of a null bytes, and execute that file.
answered Nov 18 at 0:52
muru
35.1k581154
You cannot execute a variable like that because:
- the kernel executes files,
- the shell can execute command lines stored in variables, but it cannot interpret binary data
- storing a binary file's contents in a variable will likely not work well, because null bytes may be present in the file (and you can't have null bytes in variables of most shells)
- even if you used process substitution to get a temporary file with the contents of that variable, process substitution file handles won't be executable
So you'll have to store the contents in a file, make that file executable, hope that nothing got missed because of a null bytes, and execute that file.
answered Nov 18 at 0:52
muru
35.1k581154
answered Nov 18 at 0:52
muru
35.1k581154
answered Nov 18 at 0:52
muru
35.1k581154
answered Nov 18 at 0:52
muru
35.1k581154
35.1k581154
add a comment |
add a comment |
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