ov

🎑Feature-rich terminal-based text viewer. It is a so-called terminal pager.

Description

ov provides a more convenient function by separating text, not only the pager function to display at the terminal size.

* Specify a fixed line to be displayed as a header. * Table-formatted text can be interpreted as a column by the delimiter. * Text can be interpreted as a section by splitting the line with a delimiter. * Supports files larger than memory.

Programming language: Go

License: MIT License

Tags: Command Line     CLI     Tail     Terminal     Pager    

README

ov - feature rich terminal pager

ov is a terminal pager.

• Can be used instead of less or more. It can also be used instead of tail -f.
• ov also has an effective function for tabular text.

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• 1. Feature
• 2. Install
  • 2.1. deb package
  • 2.2. rpm package
  • 2.3. MacPorts (macOS)
  • 2.4. Homebrew(macOS or Linux)
  • 2.5. pkg (FreeBSD)
  • 2.6. Binary
  • 2.7. go install
  • 2.8. go get(details or developer version)
• 3. Usage
  • 3.1. Basic usage
  • 3.2. Config
  • 3.3. Header
  • 3.4. Column Mode
  • 3.5. Wrap/NoWrap
  • 3.6. Alternate-Rows
  • 3.7. Section
  • 3.8. Follow mode
  • 3.9. Follow all mode
  • 3.10. Follow section mode
  • 3.11. Exec mode
  • 3.12. Search
  • 3.13. Mark
  • 3.14. Watch
  • 3.15. Mouse support
• 4. Command option
• 5. Key bindings
• 6. Customize
  • 6.1. Style customization
  • 6.2. Key binding customization

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1. Feature

• Supports fixed header line display (both wrap/nowrap).
• Supports column mode, which recognizes columns by delimiter.
• Supports section-by-section movement, splitting sections by delimiter.
• Dynamic wrap/nowrap switchable.
• Supports alternating row styling.
• Shortcut keys are customizable.
• The style of the effect is customizable.
• Supports follow-mode (like tail -f).
• Supports follow-section, which is displayed when the section is updated.
• Supports following multiple files and switching when updated(follow-all).
• Supports the execution of commands that toggle both stdout and stder for display.
• Supports watch mode, which reads files on a regular basis.
• Supports incremental search and regular expression search.
• Better support for Unicode and East Asian Width.
• Support for compressed files (gzip, bzip2, zstd, lz4, xz).
• Suitable for tabular text. psql, mysql, etc...

2. Install

2.1. deb package

You can download the package from releases.

curl -L -O https://github.com/noborus/ov/releases/download/vx.x.x/ov_x.x.x-1_amd64.deb
sudo dpkg -i ov_x.x.x-1_amd64.deb

2.2. rpm package

You can download the package from releases.

sudo rpm -ivh https://github.com/noborus/ov/releases/download/vx.x.x/ov_x.x.x-1_amd64.rpm

2.3. MacPorts (macOS)

sudo port install ov

2.4. Homebrew(macOS or Linux)

brew install noborus/tap/ov

2.5. pkg (FreeBSD)

pkg install ov

2.6. Binary

You can download the binary from releases.

curl -L -O https://github.com/noborus/ov/releases/download/vx.x.x/ov_x.x.x_linux_amd64.zip
unzip ov_x.x.x_linux_amd64.zip
sudo install ov /usr/local/bin

2.7. go install

It will be installed in $GOPATH/bin by the following command.

go install github.com/noborus/ov@latest

2.8. go get(details or developer version)

First of all, download only with the following command without installing it.

go get -d github.com/noborus/ov
cd $GOPATH/src/github.com/noborus/ov

Next, to install to $GOPATH/bin, run the make install command.

make install

Or, install it in a PATH location for other users to use (For example, in /usr/local/bin).

make
sudo install ov /usr/local/bin

3. Usage

3.1. Basic usage

ov supports open file name or standard input.

ov filename

cat filename|ov

Used by other commands by setting the environment variable PAGER.

export PAGER=ov

See the ov site for more use cases.

3.2. Config

You can set style and key bindings in the setting file.

Create a .ov.yaml file in your user's home directory.

for example.

$HOME/.ov.yaml

Windows.

%USERPROFILE%/.ov.yaml

Please refer to the sample ov.yaml configuration file.

If you like less key bindings, copy ov-less.yaml and use it.

3.3. Header

The --header (-H) option fixedly displays the specified number of lines.

ov --header 1 README.md

When used with the --skip-lines option, it hides the number of lines specified by skip and then displays the header.

ov --skip-lines 1 --header 1 README.md

3.4. Column Mode

Specify the delimiter with --column-delimiter and set it to --column-mode to highlight the column.

ov --column-delimiter "," --column-mode test.csv

3.5. Wrap/NoWrap

Supports switching between wrapping and not wrapping lines.

The option is --wrap, specify --wrap=false if you do not want to wrap. After startup, toggle display with wrap (default key w).

3.6. Alternate-Rows

Alternate row styles with the --alternate-rows(-C) option The style can be set with Style customization.

ov --alternate-rows test.csv

3.7. Section

You specify --section-delimiter, you can move up and down in section units. The start of the section can be adjusted with --section-start.

[section.png](docs/section.png)

The section-delimiter is written in a regular expression (for example: "^#"). (Line breaks are not included in matching lines).

For example, if you specify "^diff" for a diff that contains multiple files, you can move the diff for each file.

3.8. Follow mode

Output appended data and move it to the bottom line (like tail -f).

ov --follow-mode /var/log/syslog

(while :; do echo random-$RANDOM; sleep 0.1; done;)|./ov  --follow-mode

3.9. Follow all mode

Same as follow-mode, and switches to the last updated file when there are multiple files.

ov --follow-all /var/log/nginx/access.log /var/log/nginx/error.log

3.10. Follow section mode

Follow mode is line-by-line, while follow section mode is section-by-section. Follow section mode displays the bottom section. The following example is displayed from the header (#) at the bottom.

ov --section-delimiter "^#" --follow-section README.md

Watch mode is a mode in which --follow-section and --section-delimiter "^\f" are automatically set.

3.11. Exec mode

Execute the command to display stdout/stderr separately. Arguments after (--) are interpreted as command arguments.

Shows the stderr screen as soon as an error occurs, when used with --follow-all.

ov --follow-all --exec -- make

3.12. Search

Search by forward search / key(default) or the backward search ? key(defualt). Search can be toggled between incremental search, regular expression search, and case sensitivity. Displayed when the following are enabled in the search input prompt:

Function	display	(Default)key	command option
Incremental search	(I)	alt+i	--incremental
Regular expression search	(R)	alt+r	--regexp-search
Case sensitive	(Aa)	alt+c	-i, --case-sensitive

3.13. Mark

Mark the display position with the m key(default). The mark is decorated with StyleMarkLine and MarkStyleWidth.

Marks can be erased individually with the M key(default). It is also possible to delete all marks with the ctrl + delete key(default).

Use the >next and <previous (default) key to move to the marked position.

3.14. Watch

ov has a watch mode that reads the file every N seconds and adds it to the end. When you reach EOF, add '\f' instead. Go further to the last section. The default is'section-delimiter', so the last loaded content is displayed.

for example.

ov --watch 1 /proc/meminfo

3.15. Mouse support

The ov makes the mouse support its control. This can be disabled with the option --disable-mouse.

If mouse support is enabled, tabs and line breaks will be interpreted correctly when copying.

Copying to the clipboard uses atotto/clipboard. For this reason, the 'xclip' or 'xsel' command is required in Linux/Unix environments.

Selecting the range with the mouse and then left-clicking will copy it to the clipboard.

Pasting in ov is done with the middle button. In other applications, it is pasted from the clipboard (often by pressing the right-click).

4. Command option

$ ov --help
ov is a feature rich pager(such as more/less).
It supports various compressed files(gzip, bzip2, zstd, lz4, and xz).

Usage:
  ov [flags]

Flags:
  -C, --alternate-rows             alternately change the line color
  -i, --case-sensitive             case-sensitive in search
  -d, --column-delimiter string    column delimiter (default ",")
  -c, --column-mode                column mode
      --completion string          generate completion script [bash|zsh|fish|powershell]
      --config string              config file (default is $HOME/.ov.yaml)
      --debug                      debug mode
      --disable-mouse              disable mouse support
  -e, --exec                       exec command
  -X, --exit-write                 output the current screen when exiting
  -a, --exit-write-after int       NUM after the current lines when exiting
  -b, --exit-write-before int      NUM before the current lines when exiting
  -A, --follow-all                 follow all
  -f, --follow-mode                follow mode
      --follow-section             follow section
  -H, --header int                 number of header rows to fix
  -h, --help                       help for ov
      --help-key                   display key bind information
      --incsearch                  incremental search (default true)
  -n, --line-number                line number mode
  -F, --quit-if-one-screen         quit if the output fits on one screen
      --regexp-search              regular expression search
      --section-delimiter string   section delimiter
      --section-start int          section start position
      --skip-lines int             skip the number of lines
  -x, --tab-width int              tab stop width (default 8)
  -v, --version                    display version information
  -T, --watch int                  watch mode interval
  -w, --wrap                       wrap mode (default true)

It can also be changed after startup.

5. Key bindings

 [Escape], [q]                * quit
 [ctrl+c]                     * cancel
 [Q]                          * output screen and quit
 [ctrl+q]                     * set output screen and quit
 [ctrl+z]                     * suspend
 [h], [ctrl+F1], [ctrl+alt+c] * display help screen
 [ctrl+F2], [ctrl+alt+e]      * display log screen
 [ctrl+l]                     * screen sync
 [ctrl+f]                     * follow mode toggle
 [ctrl+a]                     * follow all mode toggle
 [ctrl+alt+r]                 * enable/disable mouse

    Moving

 [Enter], [Down], [ctrl+N]    * forward by one line
 [Up], [ctrl+p]               * backward by one line
 [Home]                       * go to top of document
 [End]                        * go to end of document
 [PageDown], [ctrl+v]         * forward by page
 [PageUp], [ctrl+b]           * backward by page
 [ctrl+d]                     * forward a half page
 [ctrl+u]                     * backward a half page
 [left]                       * scroll to left
 [right]                      * scroll to right
 [ctrl+left]                  * scroll left half screen
 [ctrl+right]                 * scroll right half screen
 [g]                          * go to line(input number)

    Move document

 []]                          * next document
 [[]                          * previous document
 [ctrl+k]                     * close current document

    Mark position

 [m]                          * mark current position
 [M]                          * remove mark current position
 [ctrl+delete]                * remove all mark
 [>]                          * move to next marked position
 [<]                          * move to previous marked position

    Search

 [/]                          * forward search mode
 [?]                          * backward search mode
 [n]                          * repeat forward search
 [N]                          * repeat backward search

    Change display

 [w], [W]                     * wrap/nowrap toggle
 [c]                          * column mode toggle
 [C]                          * alternate rows of style toggle
 [G]                          * line number toggle

    Change Display with Input

 [p], [P]                     * view mode selection
 [d]                          * column delimiter string
 [H]                          * number of header lines
 [ctrl+s]                     * number of skip lines
 [t]                          * TAB width

    Section

 [alt+d]                      * section delimiter regular expression
 [ctrl+F3], [alt+s]           * section start position
 [space]                      * next section
 [^]                          * previous section
 [9]                          * last section
 [F2]                         * follow section mode toggle

    Close and reload

 [ctrl+F9], [ctrl+alt+s]      * close file
 [F5], [ctrl+alt+l]           * reload file
 [F4], [ctrl+alt+w]           * watch mode
 [ctrl+w]                     * set watch interval

    Key binding when typing

 [alt+c]                      * case-sensitive toggle
 [alt+r]                      * regular expression search toggle
 [alt+i]                      * incremental search toggle

6. Customize

6.1. Style customization

You can customize the following items.

• StyleAlternate
• StyleHeader
• StyleOverStrike
• StyleOverLine
• StyleLineNumber
• StyleSearchHighlight
• StyleColumnHighlight
• StyleMarkLine
• StyleSectionLine

Specifies the color name for the foreground and background colors. Specify bool values for Reverse, Bold, Blink, Dim, Italic, and Underline.

[Example]

StyleAlternate:
  Background: "gray"
  Bold: true
  Underline: true

item name	value	example
Foreground	"color name" or "rgb"	"red"
Background	"color name" or "rgb"	"#2a2a2a"
Reverse	true/false	true
Bold	true/false	true
Blink	true/false	true
Dim	true/false	false
Italic	true/false	false
Underline	true/false	false

6.2. Key binding customization

You can customize key bindings.

[Example]

    down:
        - "Enter"
        - "Down"
        - "ctrl+N"
    up:
        - "Up"
        - "ctrl+p"

See ov.yaml for more information.