Navigating UNIX:
- / (refers to the root directory on the server)
- ./ (the current directory that you are in)
- ../ (parent directory of your current directory)
- pwd (shows what you current directory is - giving the full
path)
- ls (lists all the files in your current directory)
- ls -al (lists filenames + information)
- ls -alR (lists filenames + information in all
subdirectories)ls -alR | more (lists filenames + information in
all subdirectories, pausing when the screen become full)
- ls -alR > result.txt (lists filenames + information in all
subdirectories, and ouputs the results to a file instead of the
screen)
- ls *.html (lists all files ending with .html)
- ls -al /home/usr/bob/ (lists files + info for /home/usr/bob)
- cd (changes you to a new directory)
- cd images
- cd / (changes you to the root directory)
- cd /home/usr/images
- cd .. (this goes back one directory)
Moving, Copying and Deleting Files:
- mv [old name] [new name] (move/rename a file)
- cp [filename] [new filename] (copy a file)
- rm [filename] (delete a file)
- rm * (delete all files in your current directory)
- rm *.html (delete all files ending in .html in your current
directory)
Creating, Moving, Copying and Deleting Directories:
- mkdir [directoryname] (creates a new directory)
- ls -d */ (lists all directories within current directory)
- cp -r [directoryname] [new directoryname] (copy a directory
and all files/directories in it)
- rmdir [directoryname] (remove a directory if it is empty)
- rm -r [directoryname] (remove a directory and all files in
it)
Searching Files and Directories
- find / -name [filename] -print (search the whole server for
a file)
- find . -name [filename] -print (search for a file starting
with the current directory)
- find / -name [directoryname] - type d -print (search the
whole server for a direcory)
- grep [text] [filename] (search for text within a file)
- sed s/[oldtext]/[newtext]/g [filename] (searches file and
replaces all occurances of [oldtext]
- with [newtext]
File and Directory Permissions
There are three levels of file permission: read, write and
execute. In addition, there are three groups to which you can
assign permission, The file owner, the user group, and everyone.
The command chmod followed by three numbers is used to change
permissons. The first number is the permission for the owner, the
second for the group and the third for everyone. Here are how the
levels of permission translate:
- 0 = --- (no permission)
- 1 = --x (execute only)
- 2 = -w- (write only)
- 3 = -wx (write and execute)
- 4 = r-- (read only)
- 5 = r-x (read and execute)
- 6 = rw- (read and write)
- 7 = rwx (read, write and execute)
Here are the most common file permissions used:
- chmod 604 [filename] (minimum permission for www HTML file)
- chmod 705 [directoryname] (minimum permission for www
directories)
- chmod 705 [filename] (minimum permission for www scripts &
programs)
- chmod 606 [filename] (permission for datafiles used by www
scripts)
- chmod 703 [directoryname] (write-only permission for public
FTP uploading)
- chmod 755 [filename] (permission for CGI scripts)