Command-line is used basically in Linux. This is the communication means between the user and the system. It’s a very complex tool. Each command has its own key unique option, therefore documentation is key when working with a Linux system.
There are many methods to get help from the Linux command lines such as man, help, and info but are only a few we will focus on here.
When started with the –help parameter, most commands display some brief instructions about their usage. Instructions from –help parameter is rather brief as compared to others.
GNU bash, version 5.0.17(1)-release (x86_64-pc-linux-gnu) These shell commands are defined internally. Type `help' to see this list. Type `help name' to find out more about the function `name'. Use `info bash' to find out more about the shell in general. Use `man -k' or `info' to find out more about commands not in this list.
Most commands provide a manual page or a ‘man page’. This documentation comes with the software and can be accessed with the man command. For example, man mkdir
$ man mkdir
This command opens the man page for Mkdir. You can navigate through using up and down arrow keys. To exit the man page press q for quiet.
MKDIR(1) User Commands MKDIR(1) NAME mkdir - make directories SYNOPSIS mkdir [OPTION]... DIRECTORY... DESCRIPTION Create the DIRECTORY(ies), if they do not already exist. Mandatory arguments to long options are mandatory for short options too. -m, --mode=MODE set file mode (as in chmod), not a=rwx - umask -p, --parents no error if existing, make parent directories as needed -v, --verbose print a message for each created directory
The info pages are usually more detailed than the man pages and are formatted in hypertext, similar to web pages on the internet.
$ info mkdir Next: mkfifo invocation, Prev: ln invocation, Up: Special file types 12.3 ‘mkdir’: Make directories ============================== ‘mkdir’ creates directories with the specified names. Synopsis: mkdir [OPTION]... NAME... ‘mkdir’ creates each directory NAME in the order given. It reports an error if NAME already exists, unless the ‘-p’ option is given and NAME is a directory. The program accepts the following options. Also see *note Common options::. ‘-m MODE’ ‘--mode=MODE’ Set the file permission bits of created directories to MODE, which uses the same syntax as in ‘chmod’ and uses ‘a=rwx’ (read, write and execute allowed for everyone) for the point of the departure. *Note File permissions::. -----Info: (coreutils)mkdir invocation, 65 lines --Top-------------------------- Welcome to Info version 6.7. Type H for help, h for tutorial.
The locate command
The locate command searches within the database and then outputs every name that matches a given string.
$ locate note
The find command
The find command is used to search for files in the directories. Find searches a directory tree recursively. It does not maintain the database as locate command. Find requires the path to search.
Next article we will explore directories and listing of files in Linux