less

Open a file

$ less [source_file]

$ [<Space>|<b>]

$ [<G>|<g>]

$ </>[something]

$ <?>[something]

$ <F>

$ <v>

$ <q>

less [options] [file ...]

-?
    Displays help information.

-a
    Causes less to search all files for a pattern. By default, less only searches the current file.

-b n
    Sets the number of buffers to use for input files.

-c
    Causes less to repaint the screen from the top, rather than scrolling from the bottom.

-d
    Suppresses error messages displayed due to long lines that don't fit on the screen. This also disables highlighting of the lines exceeding the screen width.

-e
    Causes less to automatically exit after reaching the end of the first file.

-f
    Forces less to open files, even special files or directories that might otherwise be skipped.

-g
    Only highlights the matching string during the search instead of all instances.

-i
    Causes searches to ignore case.

-N
    Displays line numbers at the beginning of each line.

-p pattern
    Starts less by searching for the first occurrence of pattern in the file.

-Q
    Causes less to be completely silent; that is, never ring the terminal bell.

-s
    Squeezes multiple blank lines into a single blank line.

-x n
    Sets the tab stop interval to n spaces.

+command
    Specifies a command to be executed each time a new file is examined.

less is a terminal pager program that allows users to view the contents of text files, one screen at a time.

Unlike more basic pagers like more, less allows both forward and backward navigation through the file, making it significantly more user-friendly and efficient for examining large documents or output streams.

It doesn't load the entire file into memory, which allows for quickly viewing very large files. less supports a wide variety of features, including searching for patterns, navigating to specific lines, marking positions within the file, and handling multiple files simultaneously.

Its flexibility and efficiency have made it a standard tool for viewing text-based data in Unix-like operating systems.

While less excels at viewing text files, it may not be suitable for viewing binary files or files with complex formatting. Direct use on very large single-line files may still face memory issues.

less was created as a replacement for the more command, addressing some of its limitations, most notably the inability to scroll backward through a file.

It was originally written by Mark Nudelman in 1983 and has been continuously improved and maintained since then. The name less is a pun on more.

Due to its enhanced functionality, it quickly became the pager of choice in many Unix-like environments and remains a vital tool for developers and system administrators.

more(1), head(1), tail(1), cat(1), grep(1)