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https://github.com/cdepillabout/highlight

command line tool for highlighting parts of files that match a regex
https://github.com/cdepillabout/highlight

cli grep hacktoberfest haskell highlight highlighting hrep regex

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command line tool for highlighting parts of files that match a regex

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README 

        

Highlight

=========



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`highlight` is a command line program for highlighting parts of a file matching

a regex.



For example, take a look at the following file:



![non-highlighted file](/img/non-highlighted-file.png?raw=true "non-highlighted file")



`highlight` can be used to highlight the regex `cat`:



![simple highlighted file](/img/highlight-simple-example.png?raw=true "simple highlighted file")



**Table of Contents**



- [Highlight](#highlight)

    - [Uses](#uses)

        - [`highlight`](#highlight)

        - [highlight output from `grep`](#highlight-output-from-grep)

        - [`hrep`](#hrep)

    - [Installation](#installation)

    - [Other ways to highlight parts of files](#other-ways-to-highlight-parts-of-files)

    - [Contributions](#contributions)

        - [Additional flags](#additional-flags)

    - [Development](#development)

        - [Build](#build)

        - [Test](#test)



## Uses



This package installs two binaries, `highlight` and `hrep`.  The following

section explains the main uses of `highlight` and `hrep`.



### `highlight`



`highlight` is used to highlight a given regex in a file, while printing out

all lines of the file.



The short example above show how to use `highlight` to highlight a regex in a

single file.  It is also possible to use `highlight` on multiple files at once:



![multiple highlighted files](/img/highlight-multi-file-example.png?raw=true "multiple highlighted files")



`highlight` will color and stripe the filenames to make it easier to see which

line came from which file.  This also shows an example of the `--ignore-case`

option, which is similar to `grep`'s `--ignore-case` option.



### highlight output from `grep`



`highlight` has a special option for highlighting output from `grep`:



![highlight from grep](/img/highlight-from-grep.png?raw=true "highlight from grep")



This `--from-grep` option will color and stripe filenames, similar to the

previous example.



### `hrep`



With the previous `--from-grep` option to `highlight`, one unfortunate point is

that the regex has to be specified twice, once to `grep` and once to

`highlight`.



The `hrep` command can solve this for us.  It is just like the `grep` command,

but it will color and stripe filenames:



![hrep example](/img/hrep-example.png?raw=true "hrep example")



## Installation



`highlight` and `hrep` can be installed with

[`stack`](https://docs.haskellstack.org/en/stable/README/):



```sh

$ stack --resolver nightly-2017-07-03 install highlight

```



By default, `stack` will install binaries into `~/.local/bin/`.



It should also be possible to use `cabal` to install this package.



## Other ways to highlight parts of files



It is possible to highlight lines matching a given regex with `grep` two

different ways.



1.  Use a special regex that will match any line, but only highlight the part

    desired.  It would look like this:



    ```sh

    $ grep 'about|$' file-cats file-dogs file-goats

    ```



2.  Give a large `--context` flag:



    ```sh

    $ grep --context 9999 'about' file-cats file-dogs file-goats

    ```



However, neither of these will color and stripe filenames.



## Contributions



Feel free to open an

[issue](https://github.com/cdepillabout/pretty-simple/issues) or

[PR](https://github.com/cdepillabout/pretty-simple/pulls) for any

bugs/problems/suggestions/improvements.



### Additional flags



`highlight` and `hrep` do not currently support all flags and options that

`grep` does.  Ideally, `highlight` and `hrep` would be drop-in replacements for

`grep`, supporting all the same flags and options as `grep`.



If there is a flag or option you frequently use and want supported with

`highlight` or `hrep`, please feel free to open an issue or PR.  Some

flags/options will be relatively easy to support, while some may require quite

a large amount of additional code.



## Development



### Build



`highlight` and `hrep` can be built will the following command.  See the

[Installation](#installation) section above for information about `stack`.



```sh

$ stack build

```



### Test



The tests can be run with the following command:



```sh

$ stack test

```