input: automatise commands using external inputs¶
input is a way to use external data (like file in a specific format) as input
arguments. It may be seen as a something similar to
--output but for inputs.
CSV (for Comma-Separated Values) is a common format for tabular data. It is widely used in
spreadsheet software (at least at en export format). With
csv command, you can use
columns a CSV file as arguments to li commands.
To set the command, you’ll write in sequence what to do with each column of your data. For each column you can:
specify a short option name using
-s ARGUMENTS, --short ARGUMENTS(short options are the ones with a single
specify a long option name using
-l ARGUMENTS, --long ARGUMENTS(long options are the ones with two
specify a positional argument using
-p ARGUMENTS, --positional ARGUMENTS
indicate to use the column data with
ignore the column if it’s not used in the li command, using
After each column specification, you may use a filter to manage the value. So far the following filters are available:
This will split the value (on any whitespace character, discarding empty values) and repeat the option which each item. This is useful when you are using an option which can be repeated (like
-t TAG, --tag TAGwith
li blog set).
-E ARGUMENTS, --empty ARGUMENTS
Indicate what to do if the column value is empty (by default en empty string is used). You can use either
skipto skip the whole row, or
ignoreso the option will not be set at all (which is different from the default which will still set the option but with an empty string).
CSV file is read from stdin, and by default unicode is expected. You may force an encoding
By default all the rows are read, but you may want to ignore first rows (if they are used
for columns title, or if you have already handled part of the list). To do that, use the
-r ROW, --row ROW option.
When you test your command, it is better to do a dry run to see what will happen. The
-D, --debug option is here for that: if you set it, the commands won’t be actually
run, but the exact command which would be executed will be printed on screen. You should
always use this option first until you’re sure that what you want will be executed.
You may add verbosity level to help debugging. With a verbosity level of 2 (i.e.
the value read from CSV will be printed.
By default stdout and stderr of each launched command is ignored, but you can log them to
files using respectively
--log LOG and
--log-err LOG_ERR where
LOG_ERR are paths to a log file to create.
Once all the sequence and options are set, you write the li command that you want to use, with all the needed static option (i.e. options which must be used each time).
Louise as a spreadsheet with a table like this:
This one doesn’t have a body
li demo numbers
li demo numbers
She wants to use it as input data to create blog posts.
She first saves the file using CSV format, let’s say to
Then she checks
li blog set --help to get name of options to use. She’ll need to use
--title for title,
stdin for the body and
-t for tags. Louise wants to
activate comments, so she also wants to use
-C for all posts, and a tag to says it’s
coming from the spreadsheet (using
-t spreadsheet) .
The first row of the table is used for columns headers, so she’ll start at row 1 with
There is one row without body, Louise want to skip any row without body so she’ll use the
-E skip filter, just after specifying the body row.
Reading column by column, the sequence is like this:
a title which goes to the
--titlelong option of
-i -E skip
a body which goes to the stdin of
li blog. If the body is empty, the
-E skipfilter tells to skip the whole row.
internal datacolumn is not used, so it is ignored
-s t -S
the last column are the tags, so the
-tshort option is used. There are several of them separated by spaces, so the
-Sfilter is used to split the values.
First she’ll use the
-D, --debug to check that the commands which will be executed are
the expected one:
$ li input csv -D -r 1 -l title -i -E skip -x -s t -S blog set -C -t spreadsheet < ~/blog_input.csv
Everything seems fine, so she’ll actually launch the command by running the same command
line but without the
$ li input csv -r 1 -l title -i -E skip -x -s t -S blog set -C -t spreadsheet < ~/blog_input.csv
She could also have used
--log-err to check the logs of each command:
$ li input csv -r 1 -l title -i -E skip -x -s t -S --log /tmp/jp_blog_stdout.log --log-err /tmp/jp_blog_stderr.log blog set -C -t spreadsheet < ~/blog_input.csv