File commands

Command                                               Function
cat > filename                                   To create a file with some contents. To end typing press Ctrl+d.
The > symbol means redirecting output to a file. (< for input)
cat filename                                           Displays the file contents.
cat >> filename                                   Used to append contents to a file
cp src des                                          Copy files to given location. If already exists, it will be overwritten
cp –i src des                                     Warns the user prior to overwriting the destination file
cp –r src des                                      Copies the entire directory, all its sub-directories and files.
mv old new                                        To rename an existing file or directory. –i option can also be used
mv f1 f2 f3 dir                                     To move a group of files to a directory.
mv –v old new                                    Display name of each file as it is moved.
rm file                                                Used to delete a file or group of files. –i option can also be used
rm *                                                  To delete all the files in the directory.
rm –r *                                              Deletes all files and sub-directories
rm –f *                                                To forcibly remove even write-protected files

ls                                                    Lists all files and subdirectories (blue colored) in sorted manner.
ls name                                            To check whether a file or directory exists.
ls name*                                         Short-hand notation to list out filenames of a specific pattern.
ls –a                                                Lists all files including hidden files (files beginning with .)
ls –x dirname                                      To have specific listing of a directory.
ls –R                                               Recursive listing of all files in the subdirectories

ls –l                              Long listing showing file access rights (read/write/execute-rwx for user/group/others-ugo).

cmp file1 file2                                  Used to compare two files. Displays nothing if files are identical.
wc file                                             It produces a statistics of lines (l), words(w), and characters(c).
chmod perm file                         Changes permission for the specified file. (r=4, w=2, x=1)
chmod 740 file                                           sets all rights for user, read only for groups and no rights for others