Shell Snippets
Terminal Markdown Viewer
This shell function (zsh) allows you to view a rendered version of a Markdown file in your terminal.
# shell
function mdv() {
(echo '<html>'; pulldown-cmark < "$1" ; echo '</html>') | elinks
}
Requires pulldown-cmark (cargo install pulldown-cmark) and elinks.
Dasherise Text
This converts text like 'Some sample story--name' to 'some-sample-story-name':
echo 'Some sample story--name' | tr '[:upper:]' '[:lower:]' | tr -s ' ' -
The first tr makes the text lowercase, the second tr replaces spaces with
dashes. The -s option squeezes mutiple occurances of space or dash into a
single space or dash.
Send Raw Email
# shell
sendmail -t < mail.txt
Show Process Running on Port
# shell
lsof -i :3000
tar Pipe
Merge files from one location to another
# shell
tar cf - app skin | tar -C magento-dev -xf -
This will overwrite existing files and add new ones, respecting the directory hierarchy.
xargs
list files returned by locate with spaces in the path (the -0 does the necessary magic)
# shell
locate -0 quotes.db | xargs -0 -L 1 ls -l
Calculate Digests With OpenSSL
# shell
openssl sha -sha256 ~/Downloads/rust-1.3.0-x86_64-apple-darwin.pkg
rsync With Progress Information
# shell
rsync -avhP
Add -z option to use compression.
rsync to Host With Non-standard Port
rsync -avz -e "ssh -p PORT" user@host:/path/ /path/
List Commands Used by Popularity
Works best if you have a long command history. I have HISTSIZE=25000 in my zsh config.
# shell
history | awk '{ print $2 }' |sort | uniq -c | sort -n -r | less
Sample Output
1503 cd
1290 ls
1271 vim
1227 g
1100 ag
1075 gco
1016 ts
873 t
868 gs
729 gp
710 ssh
702 rspec
581 rake
485 cargo
431 cat
362 brew
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Fast, Pretty ZSH Prompt
https://github.com/edkolev/promptline.vim
Copy Sample Files
In Rails projects it isn't uncommon to have a bunch of sample configuration files, the non-sample versions of which are not tracked in git (such as database.yml). The following snippet will copy the samples to their destination:
for file in *.sample; do cp ${file} $(echo "$file" | sed 's/\.sample$//'); done
Command Line QR Codes
Using qrencode (it looks better in a shell).
qrencode -m 2 -t utf8 -o - 'Hello QR Code!'
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