inslice

Extracting specific columns and rows from a chunk of text is a common task one needs to do in the command-line, whether it's from files or standard input. However, current ways of doing so, such as awk or tail, are not the most straightforward or intuitive, especially since they typically require special syntax or invocations to achieve the task at hand.

inslice is a command-line utility written in Rust that aims to address this problem, by allowing one to easily filter input text by columns and rows in a literal and explicit manner using column and row numbers. It is made up of two separate binaries, colslc and rowslc, that operate on columns and rows respectively, and can be used in conjunction to achieve the desired output. This follows the Unix philosophy of writing programs that do one thing and do it well, and that work together.

To draw similarities to existing equivalent commands, see Comparisons.

Installation

Pre-Built Binaries

Pre-built colslc and rowslc binaries compiled for various target platforms can be found under the Releases section of this repository.

Cargo

To install colslc and rowslc using the cargo toolchain:

shell cargo install inslice

Usage

colslc

``` colslc 1.0.0

Jace Tan jaceys.tan@gmail.com

A command-line utility for filtering input text by columns and writing them to standard output

USAGE: colslc [OPTIONS] [--] [PATH]

ARGS: Path to input file. To read from standard input, specify - as the path. If no path is provided, the default behaviour will be to read from standard input

FLAGS: -h, --help Print help information

-V, --version
        Print version information

OPTIONS: -d, --delimiter Optional delimiter to use for splitting input text into columns. If no delimiter is provided, the default behaviour will be to split by any amount of whitespace

-f, --filters <FILTERS>...
        Filters to be applied, using column numbers to denote which columns from the input text
        should be retained. Multiple filters can be applied, the result of which is their union.
        The following are accepted formats for filters, with column indexing starting from one,
        beginning from the left-most column:

        * [n] - an exact filter for selecting the n'th column

        * [n:m] - a range-based filter for selecting the n'th to m'th (inclusive) columns

        * [n:] - a range-based filter for selecting the n'th to last (inclusive) columns

        * [:n] - a range-based filter for selecting the first to n'th (inclusive) columns

        * [:n] - a range-based filter for selecting the first to last (inclusive) columns

        Example:

        `colslc - -f 1 4:6` will result in the 1st, 4th, 5th, and 6th columns of the input text
        provided from standard input being written to standard output, separated by whitespace.

```

rowslc

``` rowslc 1.0.0

Jace Tan jaceys.tan@gmail.com

A command-line utility for filtering input text by rows and writing them to standard output

USAGE: rowslc [OPTIONS] [--] [PATH]

ARGS: Path to input file. To read from standard input, specify - as the path. If no path is provided, the default behaviour will be to read from standard input

FLAGS: -h, --help Print help information

-V, --version
        Print version information

OPTIONS: -f, --filters ... Filters to be applied, using row numbers to denote which rows from the input text should be retained. Multiple filters can be applied, the result of which is their union. The following are accepted formats for filters, with row indexing starting from one, beginning from the top-most row:

        * [n] - an exact filter for selecting the n'th row

        * [n:m] - a range-based filter for selecting the n'th to m'th (inclusive) rows

        * [n:] - a range-based filter for selecting the n'th to last (inclusive) rows

        * [:n] - a range-based filter for selecting the first to n'th (inclusive) rows

        * [:n] - a range-based filter for selecting the first to last (inclusive) rows

        Example:

        `rowslc - -f 1 4:6` will result in the 1st, 4th, 5th, and 6th rows of the input text
        provided from standard input being written to standard output, separated by a newline.

```

Comparisons

For the given input file:

shell $ cat src/testdata/input.txt REPOSITORY TAG IMAGE ID CREATED SIZE vault 1.8.4 dc15db720d79 2 days ago 186MB redis 6.2-alpine 6960a2858b36 3 days ago 31.3MB postgres 14.0-alpine ae192c4d3ada 17 months ago 152MB traefik 2.5 72bfc37343a4 18 months ago 68.9MB

colslc

awk

shell cat src/testdata/input.txt | awk '{ print $1, $4, $5, $6}'

is equivalent to

shell cat src/testdata/input.txt | colslc -f 1 4:6

rowslc

head

shell cat src/testdata/input.txt | head -3

is equivalent to

cat src/testdata/input.txt | rowslc -f :3

tail

shell cat src/testdata/input.txt | tail +3

is equivalent to

cat src/testdata/input.txt | rowslc -f 3:

head + tail

shell cat src/testdata/input.txt | head -3 | tail +3

is equivalent to

cat src/testdata/input.txt | rowslc -f 3

License

See LICENSE.