slit

README

Slit - a modern $PAGER for noisy logs

The goal is to get more from logs than most other pagers can - and to do so in less time.

Slit supports opening a single file (for now), or reading input from stdin. Slit is runs in terminal mode, writing directly to the screen, without cluttering the terminal buffer with all the logs you are reading.

Live demo

The best way is to get Go on your system and compile yourself. It's easier than it sounds:

• Download and install from https://golang.org/dl/
• Make sure that you have $GOPATH/bin in your PATH.
• go install github.com/tigrawap/slit/cmd/slit@latest
• Done!

If you prefer pre-built binaries, head over to the releases page - https://github.com/tigrawap/slit/releases. Keep in mind, however, that they might be some commits behind master branch.

Key bindings:

Search/Filters

• / - Forward search
• ? - Backsearch
• n - Next match
• N - Previous match
• CTRL + / - Switch between CaseSensitive search and RegEx
• & - Filter: intersect
• - - Filter: exclude
• + - Filter: union
• = - Remove all filters
• U - Removes last filter
• C - Stands for "Context", switches off/on all filters, helpful to get context of current line (which is the first line, at the top of the screen)

Navigation

• f, PageDown, Space, CTRL + F - Page Down
• CTRL + D - Half page down
• b, PageUp, CTRL + B - Page Up
• CTRL + U - Half page up
• g, Home - Go to first line
• G, End - Go to last line
• Arrow down, j - Move one line down
• Arrow up, k - Move one line up
• Arrow left, Arrow right - Scroll horizontally
• <, > - Precise horizontal scrolling, 1 character a time

Misc

• K - Keep N first characters(usually containing timestamp) when navigating horizontally
  Up/Down arrows during K-mode will adjust N of kept chars
• W - Wrap/Unwrap lines
• CTRL + S - Save filtered version to file (will prompt for filepath)
• q - quit

Search modes

Both search and filters currently support the CaseSensitive and RegEx modes. To switch between modes press CTRL + / in search/filter input.

TODO: History does not preserve mode of previous searches. Will be improved soon

Note: For case-insensitive search in RegEx* mode use (?i)cOnDiTiOn
TODO: This will be replaced with a separate toggle in the future

Command line arguments

• --always-term - Always opens in term mode, even if output is short
• --debug - Enables debug messages, written to /tmp/slit.log
• --filters=nginx_php_errors - Specifies path to the file containing predefined filters or inline filters separated by semicolon (see "Filters")
• --follow -f - Follow file/stdin. All filters are applied to new data When navigating up from the end, following will be stopped and resumed upon navigating to the end shift+g, or just by scrolling down till the end
• --keep-chars=10, -K 10 - Predefines number of kept chars (see K in "Key bindings")
• --output=/output/path, -O /output/path - Sets stdin cache location, if not set tmp file used, if set file preserved
• --short-stdin-timeout=10000 - Sets maximum duration (ms) to wait for delayed short stdin
• --version - Displays version

Highlighting

• ` - (Backtick) Mark top line for highlighting (i.e. will be shown no matter what other filters are active)
• ~ - Highlight filter, i.e. search and highlight everything that matches
• h - Move to next highlighted line
• H - Move to previous highlighted line
• ctrl+h - Remove all highlights
• = - Removes filters only. Does not remove highlights via ~

Filters

• Inclusive(&): Will keep only the lines that match the pattern AND are included by previous filters
• Exclusive(-): Filters out lines that match the pattern
• Appending(+): Filters in lines that match the pattern, even if they were excluded by previous filters

Filters can be chained - the first 'append' filter (if it is the first to be used) will work as an inclusive filter. When adding filters the active line position (at the top of the screen) will remain the same (…as possible).

Chaining of filters gives you the ability to filter out all the 'noise' dynamically, and get to what you're actually looking for.

Imagine: you have a huge log file with hundreds of thousands of lines from multiple threads. All that you're interested in are logs from "Thread-10, "MainThread"; you're not interested in "send" and "receive" messages. In addition, you want to see "Exception"s, even if they're on lines that were excluded by previous filters.

The following chain of filters will output the expected result:

&Thread-10
+MainThread
-receive
-send
+Exception

Filter files

You can save the lines above to a separate file and specify its name using the command line argument --filters.

Notes:

• Empty lines are ignored
• Leading spaces before a filter sign (&, + or -) are ignored
• Trailing spaces (if present) are also part of the search string
• All filters are case-sensitive

Inline filters

You can also add semicolon separated inline filters in the argument --filters with or without filter file names (the last
should also be separated by semicolon). e.g.:

$ slit --filters="nginx_php_errors;-debug.php;+WARN" /var/log/nginx/error.log

…will apply filters from the file "nginx_php_errors", then remove lines without substring "debug.php" and add the lines
with substring "WARN".

Notes:

• The first non-whitespace character should be a valid filter sign (see "Filters"), otherwise this option item will be treated as a file name
• Leading semicolon characters are ignored
• All other rules are the same as for filters in the separate files (see "Filter files")

Filter TODOs:

• Complex include/exclude filters, which will allow: (DEBUG OR INFO) AND NOT (send OR receive OR "pipe closed")
• Filters menu for overviewing current filters, removal, reordering or disable some temporary

MIT License

Documentation

Index

• Constants
• Variables
• func ToTermboxAttr(attr ansi.RuneAttr) (fg, bg termbox.Attribute)
• type ALT_KEYMAP
• type Config
• type Fetcher
  • func (f *Fetcher) Get(ctx context.Context, from Pos) <-chan Line
  • func (f *Fetcher) GetBack(ctx context.Context, fromPos Pos) <-chan Line
  • func (f *Fetcher) Search(ctx context.Context, from Pos, searchFunc filters.SearchFunc) (pos Pos)
  • func (f *Fetcher) SearchBack(ctx context.Context, from Pos, searchFunc filters.SearchFunc) (pos Pos)
  • func (f *Fetcher) SearchBackHighlighted(ctx context.Context, from Pos) (pos Pos)
  • func (f *Fetcher) SearchHighlighted(ctx context.Context, from Pos) (pos Pos)
• type Focusing
• type Line
• type LineNo
• type Navigator
• type Offset
• type Pos
  • func (l Pos) String() string
• type PosLine
• type Slit
  • func New(f *os.File) *Slit
  • func NewFromFilepath(path string) (*Slit, error)
  • func NewFromStdin() (*Slit, error)
  • func NewFromStream(ch chan string) (*Slit, error)
  • func (s *Slit) CanFitDisplay(ctx context.Context) bool
  • func (s *Slit) Display()
  • func (s *Slit) GetFile() *os.File
  • func (s *Slit) Init()
  • func (s *Slit) SetFilters(f []*filters.Filter)
  • func (s *Slit) SetFollow(b bool)
  • func (s *Slit) SetKeepChars(i int)
  • func (s *Slit) SetOutPath(path string)
  • func (s *Slit) Shutdown()
• type View

Constants

const (
	POS_UNKNOWN      = -2
	POS_FILTERED_OUT = -1
)

const (
	NO_ACTION action = iota
	ACTION_QUIT
	ACTION_RESET_FOCUS
)

Variables

var POS_NOT_FOUND = Pos{-1, -1}

Functions

func ToTermboxAttr

func ToTermboxAttr(attr ansi.RuneAttr) (fg, bg termbox.Attribute)

Types

type ALT_KEYMAP

type ALT_KEYMAP uint

const (
	NOT_ESCAPE ALT_KEYMAP = iota
	ESC
	ALT_LEFT_ARROW
	ALT_RIGHT_ARROW
	ALT_BACKSPACE
	ALT_D
)

type Config

type Config struct {
	// contains filtered or unexported fields
}

type Fetcher

type Fetcher struct {
	// contains filtered or unexported fields
}

func (*Fetcher) Get

func (f *Fetcher) Get(ctx context.Context, from Pos) <-chan Line

Get returns channel for yielding lines. Channel will be closed when no more lines to send Client should close context when no more lines needed

func (*Fetcher) GetBack

func (f *Fetcher) GetBack(ctx context.Context, fromPos Pos) <-chan Line

func (*Fetcher) Search

func (f *Fetcher) Search(ctx context.Context, from Pos, searchFunc filters.SearchFunc) (pos Pos)

Search returns position of next matching search

func (*Fetcher) SearchBack

func (f *Fetcher) SearchBack(ctx context.Context, from Pos, searchFunc filters.SearchFunc) (pos Pos)

SearchBack returns position of next matching back-search

func (*Fetcher) SearchBackHighlighted

func (f *Fetcher) SearchBackHighlighted(ctx context.Context, from Pos) (pos Pos)

SearchBack returns position of next matching back-search

func (*Fetcher) SearchHighlighted

func (f *Fetcher) SearchHighlighted(ctx context.Context, from Pos) (pos Pos)

Search returns position of next matching search

type Focusing

type Focusing interface {
	View
	// contains filtered or unexported methods
}

type Line

type Line struct {
	Str ansi.Astring
	Pos
	Highlighted bool
}

type LineNo

type LineNo int64

type Navigator

type Navigator interface {
	Focusing
	// contains filtered or unexported methods
}

type Offset

type Offset int64

type Pos

type Pos struct {
	Line   LineNo
	Offset Offset
}

func (Pos) String

func (l Pos) String() string

type PosLine

type PosLine struct {
	Pos
	// contains filtered or unexported fields
}

type Slit

type Slit struct {
	// contains filtered or unexported fields
}

Slit is a configured instance of the pager, ready to be displayed

func New

func New(f *os.File) *Slit

func NewFromFilepath

func NewFromFilepath(path string) (*Slit, error)

func NewFromStdin

func NewFromStdin() (*Slit, error)

func NewFromStream

func NewFromStream(ch chan string) (*Slit, error)

func (*Slit) CanFitDisplay

func (s *Slit) CanFitDisplay(ctx context.Context) bool

func (*Slit) Display

func (s *Slit) Display()

Invoke the Slit UI

func (*Slit) GetFile

func (s *Slit) GetFile() *os.File

Returns input file, original or cache file when reading from stdin

func (*Slit) Init

func (s *Slit) Init()

Invoke the Slit UI

func (*Slit) SetFilters

func (s *Slit) SetFilters(f []*filters.Filter)

Set initial filters

func (*Slit) SetFollow

func (s *Slit) SetFollow(b bool)

Set whether to follow file/stdin

func (*Slit) SetKeepChars

func (s *Slit) SetKeepChars(i int)

Set initial num of chars kept during horizontal scrolling

func (*Slit) SetOutPath

func (s *Slit) SetOutPath(path string)

Set explicit stdin cache location

func (*Slit) Shutdown

func (s *Slit) Shutdown()

Shutdown and cleanup this pager instance. After instance shutdown, it cannot be displayed again

type View

type View interface {
}