Man page for file permission numbers
Is there a man page for the file permission numbers?
I'm specifically talking about
r = 4
w = 2
x = 1
I can never remember them and I have to google it every time I need to set permissions besides 755. I don't think I'm alone, either, since there's even a site that calculates the number for you.
I just realized the man page for chmod
doesn't have any description of the numbers and I can't figure out what other page would have them. I guess an info
page would work as well, since apparently it comes pre-installed (I have arch; I'd have thought I'd have had to install that one myself--apparently not). It would be a lot easier for me if I could just refer to an 'on-line' man page (I use 'on-line' in the sense used in man man
).
permissions man chmod
add a comment |
Is there a man page for the file permission numbers?
I'm specifically talking about
r = 4
w = 2
x = 1
I can never remember them and I have to google it every time I need to set permissions besides 755. I don't think I'm alone, either, since there's even a site that calculates the number for you.
I just realized the man page for chmod
doesn't have any description of the numbers and I can't figure out what other page would have them. I guess an info
page would work as well, since apparently it comes pre-installed (I have arch; I'd have thought I'd have had to install that one myself--apparently not). It would be a lot easier for me if I could just refer to an 'on-line' man page (I use 'on-line' in the sense used in man man
).
permissions man chmod
1
I am having trouble finding a man page that doesn't list the mode bits in it. The GNU man page it sounds like you'd have certainly does: "The second digit selects permissions for the user who owns the file: read (4), write (2), and execute (1)". Are you sure it's not there?
– Michael Homer
2 hours ago
@MichaelHomer Yeah, I should have read more carefully. I was looking for a table. Terrible laziness on my part all day today.
– malan
2 hours ago
1
I remember it in terms of postion, rwx, and convert from binary. So "r" is 100, "w" is 010, "x" is 001. In binary that means r=4, w=2, x=1. When you see enoughls -l
output that "rwx" order eventually gets stuck in your mind :-)
– Stephen Harris
2 hours ago
@StephenHarris I very much expected this: someone to answer the question and then give me a helpful mnemonic so that I don't even need to look it up anymore. Thanks!
– malan
1 hour ago
Which operating system?
– ctrl-alt-delor
37 mins ago
add a comment |
Is there a man page for the file permission numbers?
I'm specifically talking about
r = 4
w = 2
x = 1
I can never remember them and I have to google it every time I need to set permissions besides 755. I don't think I'm alone, either, since there's even a site that calculates the number for you.
I just realized the man page for chmod
doesn't have any description of the numbers and I can't figure out what other page would have them. I guess an info
page would work as well, since apparently it comes pre-installed (I have arch; I'd have thought I'd have had to install that one myself--apparently not). It would be a lot easier for me if I could just refer to an 'on-line' man page (I use 'on-line' in the sense used in man man
).
permissions man chmod
Is there a man page for the file permission numbers?
I'm specifically talking about
r = 4
w = 2
x = 1
I can never remember them and I have to google it every time I need to set permissions besides 755. I don't think I'm alone, either, since there's even a site that calculates the number for you.
I just realized the man page for chmod
doesn't have any description of the numbers and I can't figure out what other page would have them. I guess an info
page would work as well, since apparently it comes pre-installed (I have arch; I'd have thought I'd have had to install that one myself--apparently not). It would be a lot easier for me if I could just refer to an 'on-line' man page (I use 'on-line' in the sense used in man man
).
permissions man chmod
permissions man chmod
asked 2 hours ago
malan
587418
587418
1
I am having trouble finding a man page that doesn't list the mode bits in it. The GNU man page it sounds like you'd have certainly does: "The second digit selects permissions for the user who owns the file: read (4), write (2), and execute (1)". Are you sure it's not there?
– Michael Homer
2 hours ago
@MichaelHomer Yeah, I should have read more carefully. I was looking for a table. Terrible laziness on my part all day today.
– malan
2 hours ago
1
I remember it in terms of postion, rwx, and convert from binary. So "r" is 100, "w" is 010, "x" is 001. In binary that means r=4, w=2, x=1. When you see enoughls -l
output that "rwx" order eventually gets stuck in your mind :-)
– Stephen Harris
2 hours ago
@StephenHarris I very much expected this: someone to answer the question and then give me a helpful mnemonic so that I don't even need to look it up anymore. Thanks!
– malan
1 hour ago
Which operating system?
– ctrl-alt-delor
37 mins ago
add a comment |
1
I am having trouble finding a man page that doesn't list the mode bits in it. The GNU man page it sounds like you'd have certainly does: "The second digit selects permissions for the user who owns the file: read (4), write (2), and execute (1)". Are you sure it's not there?
– Michael Homer
2 hours ago
@MichaelHomer Yeah, I should have read more carefully. I was looking for a table. Terrible laziness on my part all day today.
– malan
2 hours ago
1
I remember it in terms of postion, rwx, and convert from binary. So "r" is 100, "w" is 010, "x" is 001. In binary that means r=4, w=2, x=1. When you see enoughls -l
output that "rwx" order eventually gets stuck in your mind :-)
– Stephen Harris
2 hours ago
@StephenHarris I very much expected this: someone to answer the question and then give me a helpful mnemonic so that I don't even need to look it up anymore. Thanks!
– malan
1 hour ago
Which operating system?
– ctrl-alt-delor
37 mins ago
1
1
I am having trouble finding a man page that doesn't list the mode bits in it. The GNU man page it sounds like you'd have certainly does: "The second digit selects permissions for the user who owns the file: read (4), write (2), and execute (1)". Are you sure it's not there?
– Michael Homer
2 hours ago
I am having trouble finding a man page that doesn't list the mode bits in it. The GNU man page it sounds like you'd have certainly does: "The second digit selects permissions for the user who owns the file: read (4), write (2), and execute (1)". Are you sure it's not there?
– Michael Homer
2 hours ago
@MichaelHomer Yeah, I should have read more carefully. I was looking for a table. Terrible laziness on my part all day today.
– malan
2 hours ago
@MichaelHomer Yeah, I should have read more carefully. I was looking for a table. Terrible laziness on my part all day today.
– malan
2 hours ago
1
1
I remember it in terms of postion, rwx, and convert from binary. So "r" is 100, "w" is 010, "x" is 001. In binary that means r=4, w=2, x=1. When you see enough
ls -l
output that "rwx" order eventually gets stuck in your mind :-)– Stephen Harris
2 hours ago
I remember it in terms of postion, rwx, and convert from binary. So "r" is 100, "w" is 010, "x" is 001. In binary that means r=4, w=2, x=1. When you see enough
ls -l
output that "rwx" order eventually gets stuck in your mind :-)– Stephen Harris
2 hours ago
@StephenHarris I very much expected this: someone to answer the question and then give me a helpful mnemonic so that I don't even need to look it up anymore. Thanks!
– malan
1 hour ago
@StephenHarris I very much expected this: someone to answer the question and then give me a helpful mnemonic so that I don't even need to look it up anymore. Thanks!
– malan
1 hour ago
Which operating system?
– ctrl-alt-delor
37 mins ago
Which operating system?
– ctrl-alt-delor
37 mins ago
add a comment |
2 Answers
2
active
oldest
votes
man chmod
is likely to give you the command line tool. This may include some text that is easy to miss
The second digit selects permissions for the user who owns the file: read (4), write (2), and execute (1)
If you do man 2 chmod
then you get the system call that actually does the work. This is harder to read, but does include the magic numbers:
S_IRUSR (00400) read by owner
S_IWUSR (00200) write by owner
S_IXUSR (00100) execute/search by owner ("search" applies for direc-
tories, and means that entries within the directory
can be accessed)
S_IRGRP (00040) read by group
S_IWGRP (00020) write by group
S_IXGRP (00010) execute/search by group
S_IROTH (00004) read by others
S_IWOTH (00002) write by others
S_IXOTH (00001) execute/search by others
It also provides some other magic values:
S_ISUID (04000) set-user-ID (set process effective user ID on
execve(2))
S_ISGID (02000) set-group-ID (set process effective group ID on
execve(2); mandatory locking, as described in
fcntl(2); take a new file's group from parent direc-
tory, as described in chown(2) and mkdir(2))
S_ISVTX (01000) sticky bit (restricted deletion flag, as described in
unlink(2))
Any idea what theS_I
prefix stands for?
– undercat
2 hours ago
2
@undercat I always guessed it was "stat" "inode"... but that's just a guess and probably totally wrong :-)
– Stephen Harris
2 hours ago
add a comment |
If you have Gnu chmod
, then you can do it symbolically, e.g. chmod u+rw,g+r «file-name»
Gnu chmod
is available on most Gnu/Linux systems, and can be installed on other systems.
add a comment |
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2 Answers
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2 Answers
2
active
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oldest
votes
man chmod
is likely to give you the command line tool. This may include some text that is easy to miss
The second digit selects permissions for the user who owns the file: read (4), write (2), and execute (1)
If you do man 2 chmod
then you get the system call that actually does the work. This is harder to read, but does include the magic numbers:
S_IRUSR (00400) read by owner
S_IWUSR (00200) write by owner
S_IXUSR (00100) execute/search by owner ("search" applies for direc-
tories, and means that entries within the directory
can be accessed)
S_IRGRP (00040) read by group
S_IWGRP (00020) write by group
S_IXGRP (00010) execute/search by group
S_IROTH (00004) read by others
S_IWOTH (00002) write by others
S_IXOTH (00001) execute/search by others
It also provides some other magic values:
S_ISUID (04000) set-user-ID (set process effective user ID on
execve(2))
S_ISGID (02000) set-group-ID (set process effective group ID on
execve(2); mandatory locking, as described in
fcntl(2); take a new file's group from parent direc-
tory, as described in chown(2) and mkdir(2))
S_ISVTX (01000) sticky bit (restricted deletion flag, as described in
unlink(2))
Any idea what theS_I
prefix stands for?
– undercat
2 hours ago
2
@undercat I always guessed it was "stat" "inode"... but that's just a guess and probably totally wrong :-)
– Stephen Harris
2 hours ago
add a comment |
man chmod
is likely to give you the command line tool. This may include some text that is easy to miss
The second digit selects permissions for the user who owns the file: read (4), write (2), and execute (1)
If you do man 2 chmod
then you get the system call that actually does the work. This is harder to read, but does include the magic numbers:
S_IRUSR (00400) read by owner
S_IWUSR (00200) write by owner
S_IXUSR (00100) execute/search by owner ("search" applies for direc-
tories, and means that entries within the directory
can be accessed)
S_IRGRP (00040) read by group
S_IWGRP (00020) write by group
S_IXGRP (00010) execute/search by group
S_IROTH (00004) read by others
S_IWOTH (00002) write by others
S_IXOTH (00001) execute/search by others
It also provides some other magic values:
S_ISUID (04000) set-user-ID (set process effective user ID on
execve(2))
S_ISGID (02000) set-group-ID (set process effective group ID on
execve(2); mandatory locking, as described in
fcntl(2); take a new file's group from parent direc-
tory, as described in chown(2) and mkdir(2))
S_ISVTX (01000) sticky bit (restricted deletion flag, as described in
unlink(2))
Any idea what theS_I
prefix stands for?
– undercat
2 hours ago
2
@undercat I always guessed it was "stat" "inode"... but that's just a guess and probably totally wrong :-)
– Stephen Harris
2 hours ago
add a comment |
man chmod
is likely to give you the command line tool. This may include some text that is easy to miss
The second digit selects permissions for the user who owns the file: read (4), write (2), and execute (1)
If you do man 2 chmod
then you get the system call that actually does the work. This is harder to read, but does include the magic numbers:
S_IRUSR (00400) read by owner
S_IWUSR (00200) write by owner
S_IXUSR (00100) execute/search by owner ("search" applies for direc-
tories, and means that entries within the directory
can be accessed)
S_IRGRP (00040) read by group
S_IWGRP (00020) write by group
S_IXGRP (00010) execute/search by group
S_IROTH (00004) read by others
S_IWOTH (00002) write by others
S_IXOTH (00001) execute/search by others
It also provides some other magic values:
S_ISUID (04000) set-user-ID (set process effective user ID on
execve(2))
S_ISGID (02000) set-group-ID (set process effective group ID on
execve(2); mandatory locking, as described in
fcntl(2); take a new file's group from parent direc-
tory, as described in chown(2) and mkdir(2))
S_ISVTX (01000) sticky bit (restricted deletion flag, as described in
unlink(2))
man chmod
is likely to give you the command line tool. This may include some text that is easy to miss
The second digit selects permissions for the user who owns the file: read (4), write (2), and execute (1)
If you do man 2 chmod
then you get the system call that actually does the work. This is harder to read, but does include the magic numbers:
S_IRUSR (00400) read by owner
S_IWUSR (00200) write by owner
S_IXUSR (00100) execute/search by owner ("search" applies for direc-
tories, and means that entries within the directory
can be accessed)
S_IRGRP (00040) read by group
S_IWGRP (00020) write by group
S_IXGRP (00010) execute/search by group
S_IROTH (00004) read by others
S_IWOTH (00002) write by others
S_IXOTH (00001) execute/search by others
It also provides some other magic values:
S_ISUID (04000) set-user-ID (set process effective user ID on
execve(2))
S_ISGID (02000) set-group-ID (set process effective group ID on
execve(2); mandatory locking, as described in
fcntl(2); take a new file's group from parent direc-
tory, as described in chown(2) and mkdir(2))
S_ISVTX (01000) sticky bit (restricted deletion flag, as described in
unlink(2))
edited 2 hours ago
answered 2 hours ago
Stephen Harris
25k24477
25k24477
Any idea what theS_I
prefix stands for?
– undercat
2 hours ago
2
@undercat I always guessed it was "stat" "inode"... but that's just a guess and probably totally wrong :-)
– Stephen Harris
2 hours ago
add a comment |
Any idea what theS_I
prefix stands for?
– undercat
2 hours ago
2
@undercat I always guessed it was "stat" "inode"... but that's just a guess and probably totally wrong :-)
– Stephen Harris
2 hours ago
Any idea what the
S_I
prefix stands for?– undercat
2 hours ago
Any idea what the
S_I
prefix stands for?– undercat
2 hours ago
2
2
@undercat I always guessed it was "stat" "inode"... but that's just a guess and probably totally wrong :-)
– Stephen Harris
2 hours ago
@undercat I always guessed it was "stat" "inode"... but that's just a guess and probably totally wrong :-)
– Stephen Harris
2 hours ago
add a comment |
If you have Gnu chmod
, then you can do it symbolically, e.g. chmod u+rw,g+r «file-name»
Gnu chmod
is available on most Gnu/Linux systems, and can be installed on other systems.
add a comment |
If you have Gnu chmod
, then you can do it symbolically, e.g. chmod u+rw,g+r «file-name»
Gnu chmod
is available on most Gnu/Linux systems, and can be installed on other systems.
add a comment |
If you have Gnu chmod
, then you can do it symbolically, e.g. chmod u+rw,g+r «file-name»
Gnu chmod
is available on most Gnu/Linux systems, and can be installed on other systems.
If you have Gnu chmod
, then you can do it symbolically, e.g. chmod u+rw,g+r «file-name»
Gnu chmod
is available on most Gnu/Linux systems, and can be installed on other systems.
answered 37 mins ago
ctrl-alt-delor
10.8k41957
10.8k41957
add a comment |
add a comment |
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1
I am having trouble finding a man page that doesn't list the mode bits in it. The GNU man page it sounds like you'd have certainly does: "The second digit selects permissions for the user who owns the file: read (4), write (2), and execute (1)". Are you sure it's not there?
– Michael Homer
2 hours ago
@MichaelHomer Yeah, I should have read more carefully. I was looking for a table. Terrible laziness on my part all day today.
– malan
2 hours ago
1
I remember it in terms of postion, rwx, and convert from binary. So "r" is 100, "w" is 010, "x" is 001. In binary that means r=4, w=2, x=1. When you see enough
ls -l
output that "rwx" order eventually gets stuck in your mind :-)– Stephen Harris
2 hours ago
@StephenHarris I very much expected this: someone to answer the question and then give me a helpful mnemonic so that I don't even need to look it up anymore. Thanks!
– malan
1 hour ago
Which operating system?
– ctrl-alt-delor
37 mins ago