xontrib-pipeliner 0.1.1

Easily process the lines using pipes in xonsh.

Easily process the lines using pipes in xonsh shell.

Install

xpip install -U xontrib-pipeliner
echo 'xontrib load pipeliner' >> ~/.xonshrc
# Reload xonsh

Use cases

Python way to line modification

$ ls -1 / | head -n5
bin
boot
dev
etc
home

$ ls -1 / | head -n5 | pl "line + ' is here'" | head -n 3
bin is here
boot is here
dev is here

Splitting

$ cat /etc/passwd | head -n 3
root:x:0:0:root:/root:/bin/bash
daemon:x:1:1:daemon:/usr/sbin:/usr/sbin/nologin
bin:x:2:2:bin:/bin:/usr/sbin/nologin

$ cat /etc/passwd | head -n 3 | pl "line.split(':')[6]"
/bin/bash
/usr/sbin/nologin
/usr/sbin/nologin

Imports

$ import re
$ cat /etc/passwd | head -n 3 | pl "re.sub('/bin/bash', '/usr/bin/xonsh', line)"
root:x:0:0:root:/root:/usr/bin/xonsh
daemon:x:1:1:daemon:/usr/sbin:/usr/sbin/nologin
bin:x:2:2:bin:/bin:/usr/sbin/nologin

Arrays

$ cat /etc/passwd | head -n 3 | pl "line.split(':')" | grep nologin | pl "':'.join(eval(line)[::-1])"
/usr/sbin/nologin:/usr/sbin:daemon:1:1:x:daemon
/usr/sbin/nologin:/bin:bin:2:2:x:bin

Operations chaining (Python 3.8)

Expression is lambda function and chaining of operations in Python 3.8 looks as:

$ ls -1 / | head -n3 | pl "[s:='b', line.replace(s, s.upper()+')')][-1]"
B)in
B)oot
dev

Line number

$ ls -1 / | head | pl "'*'*len(line) if num%3 == 0 else line"
***
boot
dev
***
home
initrd.img
**************
lib
lib32
*****

Multicore pipelining

By default pipeliner works using one CPU core. To use them all in parallel try ppl command:

$ head /etc/passwd | ppl "str(num) + ' ' + line.split(':')[0]"                                                                                                                                                                         
1 daemon
0 root
2 bin
4 sync
5 games
8 mail
9 news
6 man
7 lp
3 sys

Note! The order of result lines is unpredictable because lines will be processed in parallel. The num variable contains the real line number.

Thanks

• @laloch in https://github.com/xonsh/xonsh/issues/3366