cat shows nothing
My team is working on a CI environment.
A ko file, named x.ko, is always generated from the CI environment at a regular time everyday and its type is ELF 64-bit LSB relocatable.
Today, I found that the type of this ko file became data.
I'm trying to figure out the reason.
I try to cat this ko file but the output is nothing. Then, I try to cat -et x.ko, and it gives me lots of ^@^@^@^@^@^@^@^@^@^@^@^@^@^@...
Do you know what ^@^@^@^@^@^@^@^@^@ means?
files cat file-types
asked Mar 11 at 3:18
YvesYves
929823
add a comment |
My team is working on a CI environment.
A ko file, named x.ko, is always generated from the CI environment at a regular time everyday and its type is ELF 64-bit LSB relocatable.
Today, I found that the type of this ko file became data.
I'm trying to figure out the reason.
I try to cat this ko file but the output is nothing. Then, I try to cat -et x.ko, and it gives me lots of ^@^@^@^@^@^@^@^@^@^@^@^@^@^@...
Do you know what ^@^@^@^@^@^@^@^@^@ means?
files cat file-types
asked Mar 11 at 3:18
YvesYves
929823
2
^@.... that is a CTRL-@ ..... hold ctrl key and press @ ..... it is a NULL ....0byte
– jsotola
Mar 11 at 3:28
1
It is corrupted. Has it crashed?
– Rui F Ribeiro
Mar 11 at 4:26
1
You can useodto analyse binary data. However in this case, all the evidence suggests it is a lot of zero bytes (nulls).
– ctrl-alt-delor
Mar 11 at 8:14
add a comment |
My team is working on a CI environment.
A ko file, named x.ko, is always generated from the CI environment at a regular time everyday and its type is ELF 64-bit LSB relocatable.
Today, I found that the type of this ko file became data.
I'm trying to figure out the reason.
I try to cat this ko file but the output is nothing. Then, I try to cat -et x.ko, and it gives me lots of ^@^@^@^@^@^@^@^@^@^@^@^@^@^@...
Do you know what ^@^@^@^@^@^@^@^@^@ means?
files cat file-types
asked Mar 11 at 3:18
YvesYves
929823
My team is working on a CI environment.
A ko file, named x.ko, is always generated from the CI environment at a regular time everyday and its type is ELF 64-bit LSB relocatable.
Today, I found that the type of this ko file became data.
I'm trying to figure out the reason.
I try to cat this ko file but the output is nothing. Then, I try to cat -et x.ko, and it gives me lots of ^@^@^@^@^@^@^@^@^@^@^@^@^@^@...
Do you know what ^@^@^@^@^@^@^@^@^@ means?
files cat file-types
files cat file-types
asked Mar 11 at 3:18
YvesYves
929823
asked Mar 11 at 3:18
YvesYves
929823
asked Mar 11 at 3:18
YvesYves
929823
asked Mar 11 at 3:18
YvesYves
929823
asked Mar 11 at 3:18
YvesYves
929823
929823
2
^@.... that is a CTRL-@ ..... hold ctrl key and press @ ..... it is a NULL ....0byte
– jsotola
Mar 11 at 3:28
1
It is corrupted. Has it crashed?
– Rui F Ribeiro
Mar 11 at 4:26
1
You can useodto analyse binary data. However in this case, all the evidence suggests it is a lot of zero bytes (nulls).
– ctrl-alt-delor
Mar 11 at 8:14
add a comment |
2
^@.... that is a CTRL-@ ..... hold ctrl key and press @ ..... it is a NULL ....0byte
– jsotola
Mar 11 at 3:28
1
It is corrupted. Has it crashed?
– Rui F Ribeiro
Mar 11 at 4:26
1
You can useodto analyse binary data. However in this case, all the evidence suggests it is a lot of zero bytes (nulls).
– ctrl-alt-delor
Mar 11 at 8:14
2
2
^@ .... that is a CTRL-@ ..... hold ctrl key and press @ ..... it is a NULL .... 0 byte– jsotola
Mar 11 at 3:28
^@ .... that is a CTRL-@ ..... hold ctrl key and press @ ..... it is a NULL .... 0 byte– jsotola
Mar 11 at 3:28
1
1
It is corrupted. Has it crashed?
– Rui F Ribeiro
Mar 11 at 4:26
It is corrupted. Has it crashed?
– Rui F Ribeiro
Mar 11 at 4:26
1
1
You can use
od to analyse binary data. However in this case, all the evidence suggests it is a lot of zero bytes (nulls).– ctrl-alt-delor
Mar 11 at 8:14
You can use
od to analyse binary data. However in this case, all the evidence suggests it is a lot of zero bytes (nulls).– ctrl-alt-delor
Mar 11 at 8:14
add a comment |
2 Answers
2
active
oldest
votes
Your file is full of nulls, rather than empty. A regular cat will print the nulls to standard output, but your terminal will generally display them each as nothing, while cat -v represents them as ^@. ^@ represents a null byte because the byte value of "@" (0x40, or 64) xor 64 (flip bit 7) is zero.
Why it's suddenly full of nulls, we can't tell from here.
This related question may be informative about the caret representation: Are ASCII escape sequences and control characters pairings part of a standard?
answered Mar 11 at 3:22
Michael HomerMichael Homer
49.9k8137175
M. Ribeiro is clearly thinking of unix.stackexchange.com/questions/477537 .
– JdeBP
Mar 11 at 14:49
add a comment |
Be careful , cat is not the perfect tool to display data that can be binary.
A simple unix tool is od ( octal dump ).
A example of od -c -tx1
root@server:~# od -c -tx1 /etc/passwd | head
0000000 r o o t : x : 0 : 0 : r o o t :
72 6f 6f 74 3a 78 3a 30 3a 30 3a 72 6f 6f 74 3a
0000020 / r o o t : / b i n / b a s h n
2f 72 6f 6f 74 3a 2f 62 69 6e 2f 62 61 73 68 0a
0000040 d a e m o n : x : 1 : 1 : d a e
64 61 65 6d 6f 6e 3a 78 3a 31 3a 31 3a 64 61 65
0000060 m o n : / u s r / s b i n : / u
6d 6f 6e 3a 2f 75 73 72 2f 73 62 69 6e 3a 2f 75
0000100 s r / s b i n / n o l o g i n n
73 72 2f 73 62 69 6e 2f 6e 6f 6c 6f 67 69 6e 0a
so you can see that the carriage return n
edited Mar 14 at 7:26
johan
152
answered Mar 11 at 3:43
EchoMike444EchoMike444
8625
add a comment |
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2 Answers
2
active
oldest
votes
2 Answers
2
active
oldest
votes
active
oldest
votes
active
oldest
votes
Your file is full of nulls, rather than empty. A regular cat will print the nulls to standard output, but your terminal will generally display them each as nothing, while cat -v represents them as ^@. ^@ represents a null byte because the byte value of "@" (0x40, or 64) xor 64 (flip bit 7) is zero.
Why it's suddenly full of nulls, we can't tell from here.
This related question may be informative about the caret representation: Are ASCII escape sequences and control characters pairings part of a standard?
answered Mar 11 at 3:22
Michael HomerMichael Homer
49.9k8137175
M. Ribeiro is clearly thinking of unix.stackexchange.com/questions/477537 .
– JdeBP
Mar 11 at 14:49
add a comment |
Your file is full of nulls, rather than empty. A regular cat will print the nulls to standard output, but your terminal will generally display them each as nothing, while cat -v represents them as ^@. ^@ represents a null byte because the byte value of "@" (0x40, or 64) xor 64 (flip bit 7) is zero.
Why it's suddenly full of nulls, we can't tell from here.
This related question may be informative about the caret representation: Are ASCII escape sequences and control characters pairings part of a standard?
answered Mar 11 at 3:22
Michael HomerMichael Homer
49.9k8137175
M. Ribeiro is clearly thinking of unix.stackexchange.com/questions/477537 .
– JdeBP
Mar 11 at 14:49
add a comment |
Your file is full of nulls, rather than empty. A regular cat will print the nulls to standard output, but your terminal will generally display them each as nothing, while cat -v represents them as ^@. ^@ represents a null byte because the byte value of "@" (0x40, or 64) xor 64 (flip bit 7) is zero.
Why it's suddenly full of nulls, we can't tell from here.
This related question may be informative about the caret representation: Are ASCII escape sequences and control characters pairings part of a standard?
answered Mar 11 at 3:22
Michael HomerMichael Homer
49.9k8137175
Your file is full of nulls, rather than empty. A regular cat will print the nulls to standard output, but your terminal will generally display them each as nothing, while cat -v represents them as ^@. ^@ represents a null byte because the byte value of "@" (0x40, or 64) xor 64 (flip bit 7) is zero.
Why it's suddenly full of nulls, we can't tell from here.
This related question may be informative about the caret representation: Are ASCII escape sequences and control characters pairings part of a standard?
answered Mar 11 at 3:22
Michael HomerMichael Homer
49.9k8137175
answered Mar 11 at 3:22
Michael HomerMichael Homer
49.9k8137175
answered Mar 11 at 3:22
Michael HomerMichael Homer
49.9k8137175
answered Mar 11 at 3:22
Michael HomerMichael Homer
49.9k8137175
49.9k8137175
M. Ribeiro is clearly thinking of unix.stackexchange.com/questions/477537 .
– JdeBP
Mar 11 at 14:49
add a comment |
M. Ribeiro is clearly thinking of unix.stackexchange.com/questions/477537 .
– JdeBP
Mar 11 at 14:49
M. Ribeiro is clearly thinking of unix.stackexchange.com/questions/477537 .
– JdeBP
Mar 11 at 14:49
M. Ribeiro is clearly thinking of unix.stackexchange.com/questions/477537 .
– JdeBP
Mar 11 at 14:49
add a comment |
Be careful , cat is not the perfect tool to display data that can be binary.
A simple unix tool is od ( octal dump ).
A example of od -c -tx1
root@server:~# od -c -tx1 /etc/passwd | head
0000000 r o o t : x : 0 : 0 : r o o t :
72 6f 6f 74 3a 78 3a 30 3a 30 3a 72 6f 6f 74 3a
0000020 / r o o t : / b i n / b a s h n
2f 72 6f 6f 74 3a 2f 62 69 6e 2f 62 61 73 68 0a
0000040 d a e m o n : x : 1 : 1 : d a e
64 61 65 6d 6f 6e 3a 78 3a 31 3a 31 3a 64 61 65
0000060 m o n : / u s r / s b i n : / u
6d 6f 6e 3a 2f 75 73 72 2f 73 62 69 6e 3a 2f 75
0000100 s r / s b i n / n o l o g i n n
73 72 2f 73 62 69 6e 2f 6e 6f 6c 6f 67 69 6e 0a
so you can see that the carriage return n
edited Mar 14 at 7:26
johan
152
answered Mar 11 at 3:43
EchoMike444EchoMike444
8625
add a comment |
Be careful , cat is not the perfect tool to display data that can be binary.
A simple unix tool is od ( octal dump ).
A example of od -c -tx1
root@server:~# od -c -tx1 /etc/passwd | head
0000000 r o o t : x : 0 : 0 : r o o t :
72 6f 6f 74 3a 78 3a 30 3a 30 3a 72 6f 6f 74 3a
0000020 / r o o t : / b i n / b a s h n
2f 72 6f 6f 74 3a 2f 62 69 6e 2f 62 61 73 68 0a
0000040 d a e m o n : x : 1 : 1 : d a e
64 61 65 6d 6f 6e 3a 78 3a 31 3a 31 3a 64 61 65
0000060 m o n : / u s r / s b i n : / u
6d 6f 6e 3a 2f 75 73 72 2f 73 62 69 6e 3a 2f 75
0000100 s r / s b i n / n o l o g i n n
73 72 2f 73 62 69 6e 2f 6e 6f 6c 6f 67 69 6e 0a
so you can see that the carriage return n
edited Mar 14 at 7:26
johan
152
answered Mar 11 at 3:43
EchoMike444EchoMike444
8625
add a comment |
Be careful , cat is not the perfect tool to display data that can be binary.
A simple unix tool is od ( octal dump ).
A example of od -c -tx1
root@server:~# od -c -tx1 /etc/passwd | head
0000000 r o o t : x : 0 : 0 : r o o t :
72 6f 6f 74 3a 78 3a 30 3a 30 3a 72 6f 6f 74 3a
0000020 / r o o t : / b i n / b a s h n
2f 72 6f 6f 74 3a 2f 62 69 6e 2f 62 61 73 68 0a
0000040 d a e m o n : x : 1 : 1 : d a e
64 61 65 6d 6f 6e 3a 78 3a 31 3a 31 3a 64 61 65
0000060 m o n : / u s r / s b i n : / u
6d 6f 6e 3a 2f 75 73 72 2f 73 62 69 6e 3a 2f 75
0000100 s r / s b i n / n o l o g i n n
73 72 2f 73 62 69 6e 2f 6e 6f 6c 6f 67 69 6e 0a
so you can see that the carriage return n
edited Mar 14 at 7:26
johan
152
answered Mar 11 at 3:43
EchoMike444EchoMike444
8625
Be careful , cat is not the perfect tool to display data that can be binary.
A simple unix tool is od ( octal dump ).
A example of od -c -tx1
root@server:~# od -c -tx1 /etc/passwd | head
0000000 r o o t : x : 0 : 0 : r o o t :
72 6f 6f 74 3a 78 3a 30 3a 30 3a 72 6f 6f 74 3a
0000020 / r o o t : / b i n / b a s h n
2f 72 6f 6f 74 3a 2f 62 69 6e 2f 62 61 73 68 0a
0000040 d a e m o n : x : 1 : 1 : d a e
64 61 65 6d 6f 6e 3a 78 3a 31 3a 31 3a 64 61 65
0000060 m o n : / u s r / s b i n : / u
6d 6f 6e 3a 2f 75 73 72 2f 73 62 69 6e 3a 2f 75
0000100 s r / s b i n / n o l o g i n n
73 72 2f 73 62 69 6e 2f 6e 6f 6c 6f 67 69 6e 0a
so you can see that the carriage return n
edited Mar 14 at 7:26
johan
152
answered Mar 11 at 3:43
EchoMike444EchoMike444
8625
edited Mar 14 at 7:26
johan
152
edited Mar 14 at 7:26
johan
152
edited Mar 14 at 7:26
johan
152
152
answered Mar 11 at 3:43
EchoMike444EchoMike444
8625
answered Mar 11 at 3:43
EchoMike444EchoMike444
8625
answered Mar 11 at 3:43
EchoMike444EchoMike444
8625
8625
add a comment |
add a comment |
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2
^@.... that is a CTRL-@ ..... hold ctrl key and press @ ..... it is a NULL ....0byte– jsotola
Mar 11 at 3:28
1
It is corrupted. Has it crashed?
– Rui F Ribeiro
Mar 11 at 4:26
1
You can use
odto analyse binary data. However in this case, all the evidence suggests it is a lot of zero bytes (nulls).– ctrl-alt-delor
Mar 11 at 8:14