stream editor using javascript
Run npm install -g jpipe, and then use the jp command
as described:
Usage: jp [options] <expression>
A stream editor in javascript. Evaluates <expression> for each
line of STDIN, where:
_ = the current line
_line = the current line number (starting at 0)
_prev = the previous result of the expression
(starts as '' or as [value] if --initial is set)
chalk = the 'chalk' module.
other modules are included with the -m flag. For example,
'-m "module-name"' assigns 'require("module-name")' to
'moduleName'.
Options:
-h, --help output usage information
-V, --version output the version number
-m, --module [module] include a module in your expression
-r, --reduce print only the last value computed
-i, --initial [value] set the inital value of "_prev"
-s, --swallow swallow errors
-t, --trim trim whitespace from output
-n, --nonewline don't add newline (as `echo -n`)
-f, --falsey don't remove any falsy values
cat numbers.txt | jp '+_ + 10' > numbers_plus_ten.txtEach line of the file numbers.txt is assigned to the variable _, and the
result of +_ + 10 is printed to STDOUT, which is then redirected into
numbers_plus_ten.txt.
If the result of this computation is a falsey value (other than 0, which is
allowed for convenience), then it will not be output.
Some special values come bound in the expression you give jp:
_is bound to the current line of the file._lineis bound to the current line number of the file (starting at 0)._previs bound to the result of the last expression.chalkis bound to the module chalk, which is very convenient for coloring output.
any additional modules you include with the -m flag will be required, and
assigned to a camel-case variable name (module-name is assigned to
moduleName). If you wish to include globally installed modules, make
sure to add your global node_modules to NODE_PATH:
export NODE_PATH="$(npm prefix -g)/lib/node_modules:$NODE_PATH"cat text.txt | jp --falsey 'chalk.yellow(_)'cat numbers.txt | jp --reduce '+_prev + +_'cat tabular.txt | jp --reduce '+_prev + +(_.split(/\s+/)[1])'`cat text.txt | jp --module 'crypto' 'crypto.randomBytes(2).toString("hex") + " " + _'cat objs.txt | jp 'JSON.parse(_).value'cat rows.txt | jp --reduce --initial '[]' 'JSON.parse(_prev).concat(JSON.parse(_))'ls | jp '_.match(/\.js$/)? chalk.green(_):_'git log --pretty=oneline | jp '_.charAt(0) === "7" && _'yes | jp -n 'r = (Math.random() * 6) | 0;
[chalk.red, chalk.green, chalk.yellow, chalk.blue, chalk.magenta, chalk.cyan][r]
((Math.random() * 2 | 0 % 2)? "____":"_/^\\_")'