Directory ::
pwd current directory
Directory Listing ::
ls list all files in current directory
ls -a list all files in current directory includes hidden files
ls -al list all files in current directory includes hidden files with permission, ownership and size
ls -al a* list all files in current directory includes hidden files with permission, ownership and size matching a [Case]
ls -S list all files in current directory sorts files by their size
ls -r list all files in current directory sorts files in reverse order
ls -R list all files in current directory recursively below the sub-directory
ls -F list all files in current directory with extension
Copy ::
cp original_file new file inside same directory
cp original_file /dir/dir/ to a different directory
cp original_file /dir/dir/new_file to a different directory with new name
cp /dir/dir/original_file . from a different directory to current location
Move ::
mv filename /dir/ move a file from current location to different location
mv /dir/filename . move a file from different location to current location
mv original_file new_file rename a file in same location
-i (interactive) — Prompts you if the file you have selected overwrites an existing file in the destination directory.
-f (force) — Overrides the interactive mode and moves without prompting. Be very careful about using this option.
-v (verbose) — Shows the progress of the files as they are being moved.
Delete ::
rm filename deletes the file
rmdir dirname/ deletes directory [If directory is empty]
rm -rf /dir/ deletes directory and all its contents
-i (interactive) — Prompts you to confirm the deletion.
- -f (force) — Overrides interactive mode and removes the file(s) without prompting.
- -v (verbose) — Shows the progress of the files as they are being removed.
- -r (recursive) — Deletes a directory and all files and subdirectories it contains.
find . -name foo Finds the file foo in the current directory
locate tree Finds all file(s)/directory(ies) with tree. Can be tree.txt or btree
mdfind kind:folder "farm-animal-type"
File Permission ::
rw------- (600) Only the owner has read and write permissions.
-rw-r--r-- (644) Only the owner has read and write permissions; the group and others have read only.
-rwx------ (700) Only the owner has read, write, and execute permissions.
-rwxr-xr-x (755) The owner has read, write, and execute permissions; the group and others have only read and execute.
-rwx--x--x (711) The owner has read, write, and execute permissions; the group and others have only execute.
-rw-rw-rw- (666) Everyone can read and write to the file. (Be careful with these permissions.)
-rwxrwxrwx (777) Everyone can read, write, and execute. (Again, this permissions setting can be hazardous.)
r — file can be read
w — file can be written to
x — file can be executed (if it is a program)
- (dash) — specific permission has not been assigned
Directory Permission ::
drwx------ (700) Only the user can read, write in this directory.
drwxr-xr-x (755) Everyone can read the directory; users and groups have read and execute permissions.
d — a directory
- (dash) — a regular file (rather than directory or link)
l — a symbolic link to another program or file elsewhere on the system
- Identities
- u — the user who owns the file (that is, the owner)g — the group to which the user belongso — others (not the owner or the owner's group)a — everyone or all (u, g, and o)
- Permissions
- r — read accessw — write accessx — execute access
- Actions
- + — adds the permission- — removes the permission= — makes it the only permissionchmod o+w filename.txt tells the system you want to give others write permission to the file filename.txtchmod go-w filename.txt tells the system you are removing group and others write permission to the file.g+w — adds write access for the groupo-rwx — removes all permissions for othersu+x — allows the file owner to execute the filea+rw — allows everyone to read and write to the fileug+r — allows the owner and group to read the fileg=rx — allows only the group to read and execute (not write)
To change the owner of a file/directory recursively (affecting all descendants):chmod +x dir # Set a directory to be listable chmod +x file # Set a file to be executable
To change permissions bits of all files in a directory, recursively:chown -R username dir # Recursively set user chown -R username:groupname dir # Recursively set user and group
To change permissions bits of all directories:find dir -type f -exec chmod 644 {} ';' # make all files rw-r-r-
find dir -type d -exec chmod 755 {} ';' # make all directories rwxr-xr-x
It would be nice if you could just do this:
chmod -R 755 dir
Grep ::
Finding relevant word and exclusion of irrelevant word.
Finding relevant word and exclusion of irrelevant word.
grep Exception logfile.txt look for Exception
grep Exception logfile.txt | grep -v ERROR -v option to exclude
grep -c "Error" logfile.txt -c option to count the word
grep --context=6 myword logfile.txt show additional six lines after matching
egrep 'Error|Exception' logfile.txt search for either Error or Exception by executing just one command
grep Lin file1 file2 file3 search the three files for any line that contains the string Lin:
grep 'Linux is' file1 file2 file3 search for the phrase Linux is:
grep 'Linux is' * search for the phrase Linux is: in all files in the current directory
