File Commands
pwd
Print Working Directory. Find out the path of the current working directory.
cd
Change Directory. Change the current working directory
- cd somewhere to go to that directory.
- cd .. (with two dots) to move one directory up.
- cd to go straight to the home folder.
- cd- (with a hyphen) to move to your previous directory.
ls
List. View the contents of a directory.
- ls will list current directory.
- ls somewhere will list the directory named.
- ls -R will list all the files in the sub-directories as well.
- ls -a will show the hidden files.
- ls -al will list the files and directories with detailed information like the permissions, size, owner, etc.
cat
Concatenate. List the contents of a file on the standard output (stdout).
- cat filename (or filename1 filename2 filename3 …) will show content of given filename(s).
- cat -n filename will show contents with line numbers.
- cat > filename creates a new file
- cat filename1 filename2 > filename3 joins two files (1 and 2) and stores the output of them in a new file (3)
- to convert a file to upper or lower case use, cat filename | tr a-z A-Z > output.txt
cp
Copy. cp filename somewhere will copy file to the directory.
mv
Move files, and also can be used to rename files.
- mv filename somewhere will move the file to the directory.
- mv old_filename new_filename will rename the file with a new name.
mkdir
Make Directory.
- mkdir somewhere
- mkdir somewhere1/somewhere2/…/destination
- mkdir somewhere1/destination/somewhere2
rmdir
Remove Directory. Only allows you to delete empty directories.
rm
Remove Files. rm -r alternative to rmdir.
touch
Create a blank new file.
locate
Locate a file. Use locate -i to be case-insensitive. locate A*B search files contain A and B.
find
Similar to locate. But you need to give it a directory.
grep
Search through all the text in a given file.
Higher
sudo
SuperUser Do.
df
Get a report on the system’s disk space usage, shown in percentage and KBs.
df -m to show in megabytes.
du
Disk Usage. type -h to get human readable statics.
head
View the first lines of any text file.
head -n somenumber filename.txt. View fist somenumber lines of file.
tail
View last lines.
diff
Difference. Compares the contents of two files line by line. After analyzing the files, it will output the lines that do not match.
tar
Archive multiple files into a tarball.
chmod
Change the read, write, and execute permissions of files and directories.
chown
Change or transfer the ownership of a file to the specified username.
jobs
Display all current jobs along with their statuses.
Kill
Send a certain signal to an app and instructs the app to terminate itself. Kill by its PID.