| cal | Used to see the calendar of a specific month or a whole year. By default, it shows current month's calendar as output |
| case | It is the best alternative when we had to use multiple if/elif on a single variable |
| cat | Reads data from file and gives their content as output. It helps us to create, view, concatenate files |
| cc | It is used to compile the C language codes and create executables |
| ccrypt | It is a command line tool for encryption and decryption of data |
| cd | Known as change directory command. It is used to change current working directory |
| cfdisk | It displays or manipulates the disk partition table by providing a text-based “graphical” interface |
| chage | Used to view and change the user password expiry information |
| chattr | It is a file system command which is used for changing the attributes of a file in a directory |
| chfn | It allows you to change a user’s name and other details easily. chfn stands for Change finger |
| chgrp | Used to change the group ownership of a file or directory |
| chkconfig | Used to list all available services and view or update their run level settings |
| chmod | Used to change the access mode of a file |
| chown | Used to change the file Owner or group |
| chpasswd | Used to change password for multiple users at a time |
| chroot | Used to change the root directory |
| chrt | Used for manipulating the real-time attributes of a process |
| chsh | Used to change the user’s login shell(currently login shell) |
| chvt | Used to switch between the different TTY (TeleTYpewriter) terminals available |
| cksum | Used to display a CRC(Cyclic Redundancy Check) value, the byte size of the file and the name of the file to standard output |
| clear | Used to clear the terminal screen |
| cmp | Used to compare the two files byte by byte and helps you to find out whether the two files are identical or not |
| col | It is used to filter out reverse line feeds. The col utility simply reads from the standard input and writes to standard output |
| colcrt | Used to format the text processor output so that it can be viewed on Cathode Ray Tube displays |
| colrm | Removes selected columns from a file |
| column | Used to display the contents of a file in columns |
| comm | Compares two sorted files line by line and write to standard output; the lines that are common and the lines that are unique |
| compress | Used to reduce the file size. After compression, the file will be available with an added .Z extension |
| continue | Used to skip the current iteration in for, while and until loop |
| cp | Used to copy files or group of files or directory |
| cpio | cpio stands for “copy in, copy out“. It is used for processing the archive files like *.cpio or *.tar. This command can copy files to and from archives |
| cpp | It is automatically used by C compiler to transform your program before compilation |
| cron | A software utility, offered by Linux-like operating system which automates the scheduled task at a predetermined time |
| crontab | A list of commands that you want to run on a regular schedule, and also the name of the command used to manage that list |
| csplit | Used to split any file into many parts as required by the user |
| ctags | It allows quick access across the files (For example quickly seeing definition of a function) |
| cupsd | It is a type of scheduler for CUPS (Common Unit Printing System). It implements the printing system on the basis of the Internet Printing Protocol |
| curl | A tool to transfer data to or from a server, using any of the supported protocols |
| cut | For cutting out the sections from each line of files and writing the result to standard output |
| cvs | Used to store the history of a file. Whenever a file gets corrupted or anything goes wrong “cvs” help us to go back to the previous version and restore our file |