Mixing
Removing and adding permission using numerical notation on the same line
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I'm having some trouble trying to remove write permission from the owning group (g), and to add read permission to others (o) at the same time.
How would I remove some permission from the owning group and add some permission for others in the same line?
linux chmod
edited 2 days ago
ilkkachu
50.8k678140
asked Sep 9 at 20:41
Zanders2001
282
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up vote
5
down vote
favorite
I'm having some trouble trying to remove write permission from the owning group (g), and to add read permission to others (o) at the same time.
How would I remove some permission from the owning group and add some permission for others in the same line?
linux chmod
edited 2 days ago
ilkkachu
50.8k678140
asked Sep 9 at 20:41
Zanders2001
282
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Zanders2001 is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
Hello and welcome on UL. I find this question rather unclear. Don't hesitate to provide more context and example of desired behaviour so that it'll be easier for people to understand what you mean :)
– iago-lito
Sep 9 at 21:22
add a comment |Â
up vote
5
down vote
favorite
up vote
5
down vote
favorite
I'm having some trouble trying to remove write permission from the owning group (g), and to add read permission to others (o) at the same time.
How would I remove some permission from the owning group and add some permission for others in the same line?
linux chmod
edited 2 days ago
ilkkachu
50.8k678140
asked Sep 9 at 20:41
Zanders2001
282
New contributor
Zanders2001 is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
I'm having some trouble trying to remove write permission from the owning group (g), and to add read permission to others (o) at the same time.
How would I remove some permission from the owning group and add some permission for others in the same line?
linux chmod
linux chmod
edited 2 days ago
ilkkachu
50.8k678140
asked Sep 9 at 20:41
Zanders2001
282
New contributor
Zanders2001 is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
edited 2 days ago
ilkkachu
50.8k678140
asked Sep 9 at 20:41
Zanders2001
282
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Zanders2001 is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
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edited 2 days ago
ilkkachu
50.8k678140
edited 2 days ago
ilkkachu
50.8k678140
edited 2 days ago
ilkkachu
50.8k678140
50.8k678140
asked Sep 9 at 20:41
Zanders2001
282
New contributor
Zanders2001 is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
asked Sep 9 at 20:41
Zanders2001
282
asked Sep 9 at 20:41
Zanders2001
282
282
New contributor
Zanders2001 is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
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New contributor
Zanders2001 is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
Zanders2001 is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
Hello and welcome on UL. I find this question rather unclear. Don't hesitate to provide more context and example of desired behaviour so that it'll be easier for people to understand what you mean :)
– iago-lito
Sep 9 at 21:22
add a comment |Â
Hello and welcome on UL. I find this question rather unclear. Don't hesitate to provide more context and example of desired behaviour so that it'll be easier for people to understand what you mean :)
– iago-lito
Sep 9 at 21:22
Hello and welcome on UL. I find this question rather unclear. Don't hesitate to provide more context and example of desired behaviour so that it'll be easier for people to understand what you mean :)
– iago-lito
Sep 9 at 21:22
Hello and welcome on UL. I find this question rather unclear. Don't hesitate to provide more context and example of desired behaviour so that it'll be easier for people to understand what you mean :)
– iago-lito
Sep 9 at 21:22
add a comment |Â
5 Answers
5
active
oldest
votes
up vote
10
down vote
accepted
Noting the title of your question:
Removing and adding permission using numerical notation on the same line
With chmod from GNU coreutils, which you probably have on a Linux system, you could use
$ chmod -020,+004 test.txt
to do that. It works in the obvious way: middle digit for the group, 2 is for write; and last digit for "others", and 4 for read.
Being able to use + or - with a numerical mode is a GNU extension, e.g. the BSD-based chmod on my Mac gives an error for +004:
$ chmod +004 test.txt
chmod: Invalid file mode: +004
So it would be simpler, shorter, more portable and probably more readable to just use the symbolic form:
$ chmod g-w,o+r test.txt
answered 2 days ago
ilkkachu
50.8k678140
Upvoting because it's almost always best to write symbolic form rather than numeric. I've found by painful experience that people often make errors with numerical form ofchmodwhen they think they're adding permissions but are actually removing some as well. This GNU extension at least avoids that problem, but precisely because it's not POSIX, one must be careful to only use it in a domain where it's assured to be supported.
– Monty Harder
2 days ago
add a comment |Â
up vote
5
down vote
EDIT: Seeing ilkkachu's answer, made me test this, and the syntax he describes works, but the man page on my system (which I had checked) says
can be either a symbolic representation of changes to make, or an octal number representing the bit pattern for the new mode bits
which was what caused me to write the original answer (below). I guess it's a new change and that they forgot to update the man page.
Original answer below:
The title of your questions mentions "numerical notation", if by that you mean specifying modes as octal numbers, the answer is that you can't specify changes with that, only the new mode of the file(s).
answered Sep 9 at 21:17
Henrik
3,2441418
You're right, it's not on the man page. GNU likes the info pages, so you need to read them. Or the online manual which is probably generated from the same data. I added a link to it in my answer.
– ilkkachu
2 days ago
add a comment |Â
up vote
4
down vote
As the 2nd line of man page says:
chmod g-w,o+r file
$ man chmod
CHMOD(1) User Commands CHMOD(1)
NAME
chmod - change file mode bits
SYNOPSIS
chmod [OPTION]... MODE[,MODE]... FILE...
or the 1st line of chmod --help
Usage: chmod [OPTION]... MODE[,MODE]... FILE...
answered Sep 9 at 21:03
Ipor Sircer
9,1051920
add a comment |Â
up vote
3
down vote
Standardly, only the symbolic form allows adding and removing bits from the current permissions (though see @ilkkachu's answer if you're on a GNU system where chmod supports it with the numerical form as an extension).
With the numerical octal form, the number you give is the new set of permission bits, regardless of what the previous value was.
You could however get the previous value by hand and apply the modifications as a bit-logical operation.
For instance, with zsh:
zmodload zsh/stat
zstat -A mode +mode -- "$file" &&
perms=$((mode & 8#7777)) &&
chmod -- $(((perms | 4) & ~ 8#20)) "$file"
That's binary OR (|) with 4 to add the read permission to others and binary AND (&) with the binary NOT (~) of octal 20 to remove the write permissions to group.
For instance, if the previous permission bits (st_mode & 0777) were 0660 (rw-rw----), 0660 | 4 would be 0664 (rw-rw-r--), and 0664 & ~ 020 would be 0644 (rw-r--r--).
Now, I'm not sure why you'd want to do that instead of:
chmod -- g-w,o+r "$file"
answered Sep 9 at 21:43
Stéphane Chazelas
283k53522859
add a comment |Â
up vote
0
down vote
Since you didn't specify a reason for why you want to do it that way. I'll assume you don't know that it is way faster (and imho more precise) to simply set the desired mode, than to flip the flags one after another.
Explained in simplified terms:
Specify 3 numerical values for the set/unset state of all the read, write, and execute flags. For owner, group, and others all at once.
To simplify, I'll stick to 3 digits.
But you should look at the rest of the flags too when you get used to this way of doing it.
To simplify even more:
These 3 values are separate positional values, and not a three digit number. The first one sets the permissions for owner, the next one sets the permissions for group, and the third, sets the permissions for everyone else (others).
Setting the flags:
Now. Determining what each digit means is where some people get confused, but it's really simple when you first learn how it's done.
Here are the flag-values:
- 1=execute
- 2=write
- 4=read
Now, you simply do one position at a time, and add (sum) the desired flag-values together. If you want to set read and execute: 4+1=5. If you want read and write but not execute: 4+2=6.
Examples
| ### | Owner | Group | Others |
| --- | --- | --- | --- |
| 755 | RWX | R-X | R-X |
| 644 | RW- | R-- | R-- |
Extra info and more examples can be seen here:
https://linux.die.net/Linux-CLI/file-permissions.html
So if you want group and others to only have read permission, but owner should have read and write, you simply do chmod 644 FILENAME
Here's a great tutorial: Understanding Linux File Permissions
One last tip:
Remember that users need execute permission for directories to list the content.
answered 2 days ago
svin83
1091
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svin83 is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
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5 Answers
5
active
oldest
votes
5 Answers
5
active
oldest
votes
active
oldest
votes
active
oldest
votes
up vote
10
down vote
accepted
Noting the title of your question:
Removing and adding permission using numerical notation on the same line
With chmod from GNU coreutils, which you probably have on a Linux system, you could use
$ chmod -020,+004 test.txt
to do that. It works in the obvious way: middle digit for the group, 2 is for write; and last digit for "others", and 4 for read.
Being able to use + or - with a numerical mode is a GNU extension, e.g. the BSD-based chmod on my Mac gives an error for +004:
$ chmod +004 test.txt
chmod: Invalid file mode: +004
So it would be simpler, shorter, more portable and probably more readable to just use the symbolic form:
$ chmod g-w,o+r test.txt
answered 2 days ago
ilkkachu
50.8k678140
Upvoting because it's almost always best to write symbolic form rather than numeric. I've found by painful experience that people often make errors with numerical form ofchmodwhen they think they're adding permissions but are actually removing some as well. This GNU extension at least avoids that problem, but precisely because it's not POSIX, one must be careful to only use it in a domain where it's assured to be supported.
– Monty Harder
2 days ago
add a comment |Â
up vote
10
down vote
accepted
Noting the title of your question:
Removing and adding permission using numerical notation on the same line
With chmod from GNU coreutils, which you probably have on a Linux system, you could use
$ chmod -020,+004 test.txt
to do that. It works in the obvious way: middle digit for the group, 2 is for write; and last digit for "others", and 4 for read.
Being able to use + or - with a numerical mode is a GNU extension, e.g. the BSD-based chmod on my Mac gives an error for +004:
$ chmod +004 test.txt
chmod: Invalid file mode: +004
So it would be simpler, shorter, more portable and probably more readable to just use the symbolic form:
$ chmod g-w,o+r test.txt
answered 2 days ago
ilkkachu
50.8k678140
Upvoting because it's almost always best to write symbolic form rather than numeric. I've found by painful experience that people often make errors with numerical form ofchmodwhen they think they're adding permissions but are actually removing some as well. This GNU extension at least avoids that problem, but precisely because it's not POSIX, one must be careful to only use it in a domain where it's assured to be supported.
– Monty Harder
2 days ago
add a comment |Â
up vote
10
down vote
accepted
up vote
10
down vote
accepted
Noting the title of your question:
Removing and adding permission using numerical notation on the same line
With chmod from GNU coreutils, which you probably have on a Linux system, you could use
$ chmod -020,+004 test.txt
to do that. It works in the obvious way: middle digit for the group, 2 is for write; and last digit for "others", and 4 for read.
Being able to use + or - with a numerical mode is a GNU extension, e.g. the BSD-based chmod on my Mac gives an error for +004:
$ chmod +004 test.txt
chmod: Invalid file mode: +004
So it would be simpler, shorter, more portable and probably more readable to just use the symbolic form:
$ chmod g-w,o+r test.txt
answered 2 days ago
ilkkachu
50.8k678140
Noting the title of your question:
Removing and adding permission using numerical notation on the same line
With chmod from GNU coreutils, which you probably have on a Linux system, you could use
$ chmod -020,+004 test.txt
to do that. It works in the obvious way: middle digit for the group, 2 is for write; and last digit for "others", and 4 for read.
Being able to use + or - with a numerical mode is a GNU extension, e.g. the BSD-based chmod on my Mac gives an error for +004:
$ chmod +004 test.txt
chmod: Invalid file mode: +004
So it would be simpler, shorter, more portable and probably more readable to just use the symbolic form:
$ chmod g-w,o+r test.txt
answered 2 days ago
ilkkachu
50.8k678140
edited 2 days ago
answered 2 days ago
ilkkachu
50.8k678140
answered 2 days ago
ilkkachu
50.8k678140
answered 2 days ago
ilkkachu
50.8k678140
50.8k678140
Upvoting because it's almost always best to write symbolic form rather than numeric. I've found by painful experience that people often make errors with numerical form ofchmodwhen they think they're adding permissions but are actually removing some as well. This GNU extension at least avoids that problem, but precisely because it's not POSIX, one must be careful to only use it in a domain where it's assured to be supported.
– Monty Harder
2 days ago
add a comment |Â
Upvoting because it's almost always best to write symbolic form rather than numeric. I've found by painful experience that people often make errors with numerical form ofchmodwhen they think they're adding permissions but are actually removing some as well. This GNU extension at least avoids that problem, but precisely because it's not POSIX, one must be careful to only use it in a domain where it's assured to be supported.
– Monty Harder
2 days ago
Upvoting because it's almost always best to write symbolic form rather than numeric. I've found by painful experience that people often make errors with numerical form of
chmod when they think they're adding permissions but are actually removing some as well. This GNU extension at least avoids that problem, but precisely because it's not POSIX, one must be careful to only use it in a domain where it's assured to be supported.– Monty Harder
2 days ago
Upvoting because it's almost always best to write symbolic form rather than numeric. I've found by painful experience that people often make errors with numerical form of
chmod when they think they're adding permissions but are actually removing some as well. This GNU extension at least avoids that problem, but precisely because it's not POSIX, one must be careful to only use it in a domain where it's assured to be supported.– Monty Harder
2 days ago
add a comment |Â
up vote
5
down vote
EDIT: Seeing ilkkachu's answer, made me test this, and the syntax he describes works, but the man page on my system (which I had checked) says
can be either a symbolic representation of changes to make, or an octal number representing the bit pattern for the new mode bits
which was what caused me to write the original answer (below). I guess it's a new change and that they forgot to update the man page.
Original answer below:
The title of your questions mentions "numerical notation", if by that you mean specifying modes as octal numbers, the answer is that you can't specify changes with that, only the new mode of the file(s).
answered Sep 9 at 21:17
Henrik
3,2441418
You're right, it's not on the man page. GNU likes the info pages, so you need to read them. Or the online manual which is probably generated from the same data. I added a link to it in my answer.
– ilkkachu
2 days ago
add a comment |Â
up vote
5
down vote
EDIT: Seeing ilkkachu's answer, made me test this, and the syntax he describes works, but the man page on my system (which I had checked) says
can be either a symbolic representation of changes to make, or an octal number representing the bit pattern for the new mode bits
which was what caused me to write the original answer (below). I guess it's a new change and that they forgot to update the man page.
Original answer below:
The title of your questions mentions "numerical notation", if by that you mean specifying modes as octal numbers, the answer is that you can't specify changes with that, only the new mode of the file(s).
answered Sep 9 at 21:17
Henrik
3,2441418
You're right, it's not on the man page. GNU likes the info pages, so you need to read them. Or the online manual which is probably generated from the same data. I added a link to it in my answer.
– ilkkachu
2 days ago
add a comment |Â
up vote
5
down vote
up vote
5
down vote
EDIT: Seeing ilkkachu's answer, made me test this, and the syntax he describes works, but the man page on my system (which I had checked) says
can be either a symbolic representation of changes to make, or an octal number representing the bit pattern for the new mode bits
which was what caused me to write the original answer (below). I guess it's a new change and that they forgot to update the man page.
Original answer below:
The title of your questions mentions "numerical notation", if by that you mean specifying modes as octal numbers, the answer is that you can't specify changes with that, only the new mode of the file(s).
answered Sep 9 at 21:17
Henrik
3,2441418
EDIT: Seeing ilkkachu's answer, made me test this, and the syntax he describes works, but the man page on my system (which I had checked) says
can be either a symbolic representation of changes to make, or an octal number representing the bit pattern for the new mode bits
which was what caused me to write the original answer (below). I guess it's a new change and that they forgot to update the man page.
Original answer below:
The title of your questions mentions "numerical notation", if by that you mean specifying modes as octal numbers, the answer is that you can't specify changes with that, only the new mode of the file(s).
answered Sep 9 at 21:17
Henrik
3,2441418
edited 2 days ago
answered Sep 9 at 21:17
Henrik
3,2441418
answered Sep 9 at 21:17
Henrik
3,2441418
answered Sep 9 at 21:17
Henrik
3,2441418
3,2441418
You're right, it's not on the man page. GNU likes the info pages, so you need to read them. Or the online manual which is probably generated from the same data. I added a link to it in my answer.
– ilkkachu
2 days ago
add a comment |Â
You're right, it's not on the man page. GNU likes the info pages, so you need to read them. Or the online manual which is probably generated from the same data. I added a link to it in my answer.
– ilkkachu
2 days ago
You're right, it's not on the man page. GNU likes the info pages, so you need to read them. Or the online manual which is probably generated from the same data. I added a link to it in my answer.
– ilkkachu
2 days ago
You're right, it's not on the man page. GNU likes the info pages, so you need to read them. Or the online manual which is probably generated from the same data. I added a link to it in my answer.
– ilkkachu
2 days ago
add a comment |Â
up vote
4
down vote
As the 2nd line of man page says:
chmod g-w,o+r file
$ man chmod
CHMOD(1) User Commands CHMOD(1)
NAME
chmod - change file mode bits
SYNOPSIS
chmod [OPTION]... MODE[,MODE]... FILE...
or the 1st line of chmod --help
Usage: chmod [OPTION]... MODE[,MODE]... FILE...
answered Sep 9 at 21:03
Ipor Sircer
9,1051920
add a comment |Â
up vote
4
down vote
As the 2nd line of man page says:
chmod g-w,o+r file
$ man chmod
CHMOD(1) User Commands CHMOD(1)
NAME
chmod - change file mode bits
SYNOPSIS
chmod [OPTION]... MODE[,MODE]... FILE...
or the 1st line of chmod --help
Usage: chmod [OPTION]... MODE[,MODE]... FILE...
answered Sep 9 at 21:03
Ipor Sircer
9,1051920
add a comment |Â
up vote
4
down vote
up vote
4
down vote
As the 2nd line of man page says:
chmod g-w,o+r file
$ man chmod
CHMOD(1) User Commands CHMOD(1)
NAME
chmod - change file mode bits
SYNOPSIS
chmod [OPTION]... MODE[,MODE]... FILE...
or the 1st line of chmod --help
Usage: chmod [OPTION]... MODE[,MODE]... FILE...
answered Sep 9 at 21:03
Ipor Sircer
9,1051920
As the 2nd line of man page says:
chmod g-w,o+r file
$ man chmod
CHMOD(1) User Commands CHMOD(1)
NAME
chmod - change file mode bits
SYNOPSIS
chmod [OPTION]... MODE[,MODE]... FILE...
or the 1st line of chmod --help
Usage: chmod [OPTION]... MODE[,MODE]... FILE...
answered Sep 9 at 21:03
Ipor Sircer
9,1051920
answered Sep 9 at 21:03
Ipor Sircer
9,1051920
answered Sep 9 at 21:03
Ipor Sircer
9,1051920
answered Sep 9 at 21:03
Ipor Sircer
9,1051920
9,1051920
add a comment |Â
add a comment |Â
up vote
3
down vote
Standardly, only the symbolic form allows adding and removing bits from the current permissions (though see @ilkkachu's answer if you're on a GNU system where chmod supports it with the numerical form as an extension).
With the numerical octal form, the number you give is the new set of permission bits, regardless of what the previous value was.
You could however get the previous value by hand and apply the modifications as a bit-logical operation.
For instance, with zsh:
zmodload zsh/stat
zstat -A mode +mode -- "$file" &&
perms=$((mode & 8#7777)) &&
chmod -- $(((perms | 4) & ~ 8#20)) "$file"
That's binary OR (|) with 4 to add the read permission to others and binary AND (&) with the binary NOT (~) of octal 20 to remove the write permissions to group.
For instance, if the previous permission bits (st_mode & 0777) were 0660 (rw-rw----), 0660 | 4 would be 0664 (rw-rw-r--), and 0664 & ~ 020 would be 0644 (rw-r--r--).
Now, I'm not sure why you'd want to do that instead of:
chmod -- g-w,o+r "$file"
answered Sep 9 at 21:43
Stéphane Chazelas
283k53522859
add a comment |Â
up vote
3
down vote
Standardly, only the symbolic form allows adding and removing bits from the current permissions (though see @ilkkachu's answer if you're on a GNU system where chmod supports it with the numerical form as an extension).
With the numerical octal form, the number you give is the new set of permission bits, regardless of what the previous value was.
You could however get the previous value by hand and apply the modifications as a bit-logical operation.
For instance, with zsh:
zmodload zsh/stat
zstat -A mode +mode -- "$file" &&
perms=$((mode & 8#7777)) &&
chmod -- $(((perms | 4) & ~ 8#20)) "$file"
That's binary OR (|) with 4 to add the read permission to others and binary AND (&) with the binary NOT (~) of octal 20 to remove the write permissions to group.
For instance, if the previous permission bits (st_mode & 0777) were 0660 (rw-rw----), 0660 | 4 would be 0664 (rw-rw-r--), and 0664 & ~ 020 would be 0644 (rw-r--r--).
Now, I'm not sure why you'd want to do that instead of:
chmod -- g-w,o+r "$file"
answered Sep 9 at 21:43
Stéphane Chazelas
283k53522859
add a comment |Â
up vote
3
down vote
up vote
3
down vote
Standardly, only the symbolic form allows adding and removing bits from the current permissions (though see @ilkkachu's answer if you're on a GNU system where chmod supports it with the numerical form as an extension).
With the numerical octal form, the number you give is the new set of permission bits, regardless of what the previous value was.
You could however get the previous value by hand and apply the modifications as a bit-logical operation.
For instance, with zsh:
zmodload zsh/stat
zstat -A mode +mode -- "$file" &&
perms=$((mode & 8#7777)) &&
chmod -- $(((perms | 4) & ~ 8#20)) "$file"
That's binary OR (|) with 4 to add the read permission to others and binary AND (&) with the binary NOT (~) of octal 20 to remove the write permissions to group.
For instance, if the previous permission bits (st_mode & 0777) were 0660 (rw-rw----), 0660 | 4 would be 0664 (rw-rw-r--), and 0664 & ~ 020 would be 0644 (rw-r--r--).
Now, I'm not sure why you'd want to do that instead of:
chmod -- g-w,o+r "$file"
answered Sep 9 at 21:43
Stéphane Chazelas
283k53522859
Standardly, only the symbolic form allows adding and removing bits from the current permissions (though see @ilkkachu's answer if you're on a GNU system where chmod supports it with the numerical form as an extension).
With the numerical octal form, the number you give is the new set of permission bits, regardless of what the previous value was.
You could however get the previous value by hand and apply the modifications as a bit-logical operation.
For instance, with zsh:
zmodload zsh/stat
zstat -A mode +mode -- "$file" &&
perms=$((mode & 8#7777)) &&
chmod -- $(((perms | 4) & ~ 8#20)) "$file"
That's binary OR (|) with 4 to add the read permission to others and binary AND (&) with the binary NOT (~) of octal 20 to remove the write permissions to group.
For instance, if the previous permission bits (st_mode & 0777) were 0660 (rw-rw----), 0660 | 4 would be 0664 (rw-rw-r--), and 0664 & ~ 020 would be 0644 (rw-r--r--).
Now, I'm not sure why you'd want to do that instead of:
chmod -- g-w,o+r "$file"
answered Sep 9 at 21:43
Stéphane Chazelas
283k53522859
edited 2 days ago
answered Sep 9 at 21:43
Stéphane Chazelas
283k53522859
answered Sep 9 at 21:43
Stéphane Chazelas
283k53522859
answered Sep 9 at 21:43
Stéphane Chazelas
283k53522859
283k53522859
add a comment |Â
add a comment |Â
up vote
0
down vote
Since you didn't specify a reason for why you want to do it that way. I'll assume you don't know that it is way faster (and imho more precise) to simply set the desired mode, than to flip the flags one after another.
Explained in simplified terms:
Specify 3 numerical values for the set/unset state of all the read, write, and execute flags. For owner, group, and others all at once.
To simplify, I'll stick to 3 digits.
But you should look at the rest of the flags too when you get used to this way of doing it.
To simplify even more:
These 3 values are separate positional values, and not a three digit number. The first one sets the permissions for owner, the next one sets the permissions for group, and the third, sets the permissions for everyone else (others).
Setting the flags:
Now. Determining what each digit means is where some people get confused, but it's really simple when you first learn how it's done.
Here are the flag-values:
- 1=execute
- 2=write
- 4=read
Now, you simply do one position at a time, and add (sum) the desired flag-values together. If you want to set read and execute: 4+1=5. If you want read and write but not execute: 4+2=6.
Examples
| ### | Owner | Group | Others |
| --- | --- | --- | --- |
| 755 | RWX | R-X | R-X |
| 644 | RW- | R-- | R-- |
Extra info and more examples can be seen here:
https://linux.die.net/Linux-CLI/file-permissions.html
So if you want group and others to only have read permission, but owner should have read and write, you simply do chmod 644 FILENAME
Here's a great tutorial: Understanding Linux File Permissions
One last tip:
Remember that users need execute permission for directories to list the content.
answered 2 days ago
svin83
1091
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Since you didn't specify a reason for why you want to do it that way. I'll assume you don't know that it is way faster (and imho more precise) to simply set the desired mode, than to flip the flags one after another.
Explained in simplified terms:
Specify 3 numerical values for the set/unset state of all the read, write, and execute flags. For owner, group, and others all at once.
To simplify, I'll stick to 3 digits.
But you should look at the rest of the flags too when you get used to this way of doing it.
To simplify even more:
These 3 values are separate positional values, and not a three digit number. The first one sets the permissions for owner, the next one sets the permissions for group, and the third, sets the permissions for everyone else (others).
Setting the flags:
Now. Determining what each digit means is where some people get confused, but it's really simple when you first learn how it's done.
Here are the flag-values:
- 1=execute
- 2=write
- 4=read
Now, you simply do one position at a time, and add (sum) the desired flag-values together. If you want to set read and execute: 4+1=5. If you want read and write but not execute: 4+2=6.
Examples
| ### | Owner | Group | Others |
| --- | --- | --- | --- |
| 755 | RWX | R-X | R-X |
| 644 | RW- | R-- | R-- |
Extra info and more examples can be seen here:
https://linux.die.net/Linux-CLI/file-permissions.html
So if you want group and others to only have read permission, but owner should have read and write, you simply do chmod 644 FILENAME
Here's a great tutorial: Understanding Linux File Permissions
One last tip:
Remember that users need execute permission for directories to list the content.
answered 2 days ago
svin83
1091
New contributor
svin83 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 |Â
up vote
0
down vote
up vote
0
down vote
Since you didn't specify a reason for why you want to do it that way. I'll assume you don't know that it is way faster (and imho more precise) to simply set the desired mode, than to flip the flags one after another.
Explained in simplified terms:
Specify 3 numerical values for the set/unset state of all the read, write, and execute flags. For owner, group, and others all at once.
To simplify, I'll stick to 3 digits.
But you should look at the rest of the flags too when you get used to this way of doing it.
To simplify even more:
These 3 values are separate positional values, and not a three digit number. The first one sets the permissions for owner, the next one sets the permissions for group, and the third, sets the permissions for everyone else (others).
Setting the flags:
Now. Determining what each digit means is where some people get confused, but it's really simple when you first learn how it's done.
Here are the flag-values:
- 1=execute
- 2=write
- 4=read
Now, you simply do one position at a time, and add (sum) the desired flag-values together. If you want to set read and execute: 4+1=5. If you want read and write but not execute: 4+2=6.
Examples
| ### | Owner | Group | Others |
| --- | --- | --- | --- |
| 755 | RWX | R-X | R-X |
| 644 | RW- | R-- | R-- |
Extra info and more examples can be seen here:
https://linux.die.net/Linux-CLI/file-permissions.html
So if you want group and others to only have read permission, but owner should have read and write, you simply do chmod 644 FILENAME
Here's a great tutorial: Understanding Linux File Permissions
One last tip:
Remember that users need execute permission for directories to list the content.
answered 2 days ago
svin83
1091
New contributor
svin83 is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
Since you didn't specify a reason for why you want to do it that way. I'll assume you don't know that it is way faster (and imho more precise) to simply set the desired mode, than to flip the flags one after another.
Explained in simplified terms:
Specify 3 numerical values for the set/unset state of all the read, write, and execute flags. For owner, group, and others all at once.
To simplify, I'll stick to 3 digits.
But you should look at the rest of the flags too when you get used to this way of doing it.
To simplify even more:
These 3 values are separate positional values, and not a three digit number. The first one sets the permissions for owner, the next one sets the permissions for group, and the third, sets the permissions for everyone else (others).
Setting the flags:
Now. Determining what each digit means is where some people get confused, but it's really simple when you first learn how it's done.
Here are the flag-values:
- 1=execute
- 2=write
- 4=read
Now, you simply do one position at a time, and add (sum) the desired flag-values together. If you want to set read and execute: 4+1=5. If you want read and write but not execute: 4+2=6.
Examples
| ### | Owner | Group | Others |
| --- | --- | --- | --- |
| 755 | RWX | R-X | R-X |
| 644 | RW- | R-- | R-- |
Extra info and more examples can be seen here:
https://linux.die.net/Linux-CLI/file-permissions.html
So if you want group and others to only have read permission, but owner should have read and write, you simply do chmod 644 FILENAME
Here's a great tutorial: Understanding Linux File Permissions
One last tip:
Remember that users need execute permission for directories to list the content.
answered 2 days ago
svin83
1091
New contributor
svin83 is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
answered 2 days ago
svin83
1091
New contributor
svin83 is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
answered 2 days ago
svin83
1091
answered 2 days ago
svin83
1091
1091
New contributor
svin83 is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
New contributor
svin83 is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
svin83 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 |Â
add a comment |Â
Zanders2001 is a new contributor. Be nice, and check out our Code of Conduct.
Zanders2001 is a new contributor. Be nice, and check out our Code of Conduct.
Zanders2001 is a new contributor. Be nice, and check out our Code of Conduct.
Zanders2001 is a new contributor. Be nice, and check out our Code of Conduct.
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Hello and welcome on UL. I find this question rather unclear. Don't hesitate to provide more context and example of desired behaviour so that it'll be easier for people to understand what you mean :)
– iago-lito
Sep 9 at 21:22