Difference between chmod 755 and chmod 744

Julie8484 · 2017-05-03 16:36:12

chmod 755 vs chmod 744

Horizon_Brave · 2017-05-03 16:59:11

Err I love questions, the people here know this..but a tad bit of research from you could solve this one...

To understand this you need to know a bit about the linux way that permissions are handled. Basically the numbers each individually represent a different level of permission.

4 = read
2 = write
1= execute

So you add those up to give you the value of what permission you want. A chmod 7 would mean that the root user has 4+2+1 (Write+read+execute) Notice that there's three numbers after the chmod command though. The first number (7 in the first example you gave) is the "owners" priviledge. The middle number is regular users in the same group as the owner of the file. The last number is "other" users outside of the group. So the middle number is a 5. this means that it's made up of the "Read" permission and the execute permission, but it can't write to it. Now look at your 2nd example... 744 . The owner has all persmissons, write read and execute... the reg. users have 4 which is only read persmissions. And the "others" group has only read as well..

Look up Octal Permission for Unix to read a better explanation.

Julie8484 · 2017-05-03 17:16:16

Thank you :-)

nore · 2017-05-03 17:19:00

Lazy folks don't read no manuals, they google for "chmod calculator": http://www.onlineconversion.com/html_ch … ulator.htm.

Horizon_Brave · 2017-05-03 17:25:13

nore wrote:

Lazy folks don't read no manuals, they google for "chmod calculator": http://www.onlineconversion.com/html_ch … ulator.htm.

lol, a nice calculator, but it's good to know the 'why' and how behind how something works I find...

nore · 2017-05-03 17:35:00

I'm sure you understand long division algorithm too, but still use a calculator for divisions.
Read "lazy folks" as "for non professional, occasional need".

damo · 2017-05-03 17:40:49

nore wrote:

Lazy folks don't read no manuals, they google for "chmod calculator": http://www.onlineconversion.com/html_ch … ulator.htm.

The trouble with that calculator is that there is no "Total" given. How can they expect people to rely on it like that?

Head_on_a_Stick · 2017-05-03 17:55:45

nore wrote:

"chmod calculator": http://www.onlineconversion.com/html_ch … ulator.htm.

That is brilliant, thanks nore!

I don't think I ever really understood octal permissions until I saw that page explain it graphically just now; perhaps I'm dumb

geekosupremo · 2017-05-03 17:58:40

It seems to give me the info I need. What is missing for you, @damo? (@damo if you're making a joke ... I apologize I have poor contextual reading sometimes)

The "Value" row of the tool seems to give the "total".

damo · 2017-05-03 18:24:53

^ Yeah it was a bad joke Some poor people may not be able to add the values, since they couldn't calculate them in the first place ]:D

geekosupremo · 2017-05-03 18:28:54

^^ haha! Gotcha!

It was a nice refresher on WTH these values mean.

#1 2017-05-03 16:36:12

Difference between chmod 755 and chmod 744

#2 2017-05-03 16:59:11

Re: Difference between chmod 755 and chmod 744

#3 2017-05-03 17:16:16

Re: Difference between chmod 755 and chmod 744

#4 2017-05-03 17:19:00

Re: Difference between chmod 755 and chmod 744

#5 2017-05-03 17:25:13

Re: Difference between chmod 755 and chmod 744

#6 2017-05-03 17:35:00

Re: Difference between chmod 755 and chmod 744

#7 2017-05-03 17:40:49

Re: Difference between chmod 755 and chmod 744

#8 2017-05-03 17:55:45

Re: Difference between chmod 755 and chmod 744

#9 2017-05-03 17:58:40

Re: Difference between chmod 755 and chmod 744

#10 2017-05-03 18:24:53

Re: Difference between chmod 755 and chmod 744

#11 2017-05-03 18:28:54

Re: Difference between chmod 755 and chmod 744

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