useful personal oneliners in bash

one_liners.sh

#!/usr/bin/env bash


#set -e
#set -x


# generate TOC from markdown file with ## & ### titles (V2)
cat README.md \
	| grep "^##" | sed '/##.*/p;s/\(.*\)/\L\1/;s,## ,,g;s,?,,g;s, ,-,g;s,^,(#,;s,$,),' | grep -v -e "Contents$" -e "contents)$" | tr '\n' ' ' | sed 's, ##,\n##,g;s, (,](,g;s,## , * [,g;' | sed 's,^ \* ,  * ,g;  s,^\# \* ,    * ,;  s,(##,(#,;'


# generate TOC from markdown file with ## titles (V1)
cat README.md \
	| grep "^##" | sed '/##.*/p;s/\(.*\)/\L\1/;s,## ,,g;s,?,,g;s, ,-,g;s,^,(#,;s,$,),' | tr '\n' '  ' | sed 's, ##,\n##,g;s, (,](,g;s,## , * [,g;'


# generate udev rule for symlink to usb/serial device (last connected based on dmesg) according to the following ATTRS: idVendor, idProduct, product, manufacturer
# based on http://hintshop.ludvig.co.nz/show/persistent-names-usb-serial-devices/
devname="PUT THE DESIRABLE NAME FOR ALREADY CONNECTED ttyUSBN DEVICE HERE MANUALLY" # (it will be /dev/$devname)
dmesg | tail -20 | grep -e ".*usb.*Product: .*" -e ".*usb.*Manufacturer.*" -e "New USB device found" | sed 's/.*New USB device found, //g;s/.*Product: //g;s/.*Manufacturer: //g;s/idVendor=/SUBSYSTEM=="tty, ATTRS{idVendor}=="/;s/idProduct=/ATTRS{idProduct}=="/;s/,/",/g;s/$/",/;' | tail -3 | sed '2s/^/ATTRS{product}=="/;3s/^/ATTRS{manufacturer}=="/;3s,$, SYMLINK+="'"$devname"'",;' | tr '\n' ' ' | sed '1p;s/^/\necho '"'"'/;s,$,'"'"' >> /etc/udev/rules.d/99-usb-serial.rules \&\& udevadm control --reload-rules \&\& udevadm trigger,'


# just for lulz: google errors from gcc on compilation right from a terminal:
gcc app.c -o app 2>&1 1>/dev/null | grep "error:" | sed 's/.*error: /gcc /;s,[‘’],,g;s,^,echo -ne ",;s,$,\nq\n,' | googler -n 5 -C < /dev/stdout