I put this here mostly because I forget how to do it and have to make multiple starts to get it right.
ledger -f ledger.txt print \ -e 2022-1-1 > 2021.txt ledger -f ledger.txt equity -e 2022-1-1 > tempfile.txt echo >> tempfile.txt ledger -f ledger.txt print \ -b 2022-1-1 >> tempfile.txt mv tempfile.txt ledger.txt
chroot SFTP accounts
For
$DAYJOB
I had to create user accounts for customers
and give them access to
SFTP
files to/from secured areas of our server.
We wanted to use
chroot
functionality to ensure
that no customer could see other customers' data,
and prevent them from poking around
potentially sensitive areas of the server.
After a bit of trial-and-error,
I've listed the lessons-learned here
in a cook-book fashion
so that in case I ever have to do it again,
I have the steps documented.
This post was spurred to exist thanks to this Reddit post asking about creating an encrypted FTP server on OpenBSD so my reply there became the basis for this post.
Sometimes you want to turn some text
into "sarcastic Spongebob" text
so this little fragment of
awk
will make that transformation for you:
#!/usr/bin/awk -f
BEGIN { srand() }
{
n = split($0, a, //)
for (i=1; i<=n; i++) {
c=a[i]
printf("%c", rand() < 0.5 ? toupper(c) : tolower(c))
}
print ""
}
I wanted to do some full-justification of text.
So a little
awk
later,
I could set the desired width
and pipe to justify it.
#!/usr/bin/awk -f
BEGIN {c = "COLUMNS" in ENVIRON ? ENVIRON["COLUMNS"] : 80}
{
if (NF > 1) {
s = $0
wc = split(s, a)
gsub(FS, "", s)
totalfill = c - length(s)
fill = totalfill / (wc - 1)
intfill = int(fill)
errdelta = fill - intfill
err = 0.5
printf(a[1])
for (i=2; i<=length(a); i++) {
width = intfill
err += errdelta
if (err >= 1) {
++width
err -= 1
}
printf("%*s%s", width, " ", a[i])
}
printf("\n")
} else print
}
Most Linux, BSD, MacOS machines
come with
/usr/share/dict/words
so a little
awk,
grep,
and other shell utilities
can find some interesting words.
Our daughter wanted to
"freeze dance"
(music plays,
stopping at random intervals,
at which the dancing kids freeze in place
until the music resumes).
So what is a geek dad to do?
Load up a playlist of kids' music in
cmus,
start playing the music,
and let the shell randomly freeze and resume the music
while true ; do sleep $(( $RANDOM % 15 + 5)) ; cmus-remote -u ; sleep 4; cmus-remote -u ; done
This does as
sleep
for some random interval between
5
and
20
seconds, then does as
sleep
for
4
seconds before unpausing the music.
You could do something similar with
mpd/mpc
if you prefer them.
Over on Twitter
I was having a discussion about creating a
mollyguard
to protect yourself from accidentally rebooting the wrong machine
by requiring you to type the hostname
of the machine you wanted to reboot.
If you need such,
you can add these functions to your
~/.bashrc
or
~/.profile
to create such a
reboot
function.
Note:
The function shown on Twitter had the logic reversed
so make sure you get the "=" and "!=" correct.
If
$1
equals
the hostname,
you want to proceed with the shutdown;
if they are
not equal
you want a warning.
reboot() { [ "x$1" = "x$(hostname)" ] && sudo /sbin/shutdown -r now || echo "Failed to specify $(hostname)" ; }
halt() { [ "x$1" = "x$(hostname)" ] && sudo /sbin/shutdown -p now || echo "Failed to specify $(hostname)" ; }
If you run on OpenBSD
you can specify
doas
instead of
sudo.
While I'm not sure when others would use this I wanted to find the Nth word of a text file so I used this to find the, say, 318th word of the document:
tr -cs "a-zA-Z'" '\012' < document.txt | sed -n '318{p;q;}'
Yes, it can get tripped up by non-Latin characters, hyphenated words, or other edge-cases, but for my 7-bit ASCII input text, it did the job.
Occasionally I have multiple windows open in
vim
and want to add all of those files to
git.
Rather than specifying each filename explicitly,
I use this:
windo !git add %
Occasionally I want to
diff
one or more files in
git
and, if everything looks good,
then add them.
To do so,
I often take advantage of
bash's
^
notation to do a replacement:
git diff -- file1.txt file2.txt ^diff^add git commit -m "Looks good to me"
The second command replaces
diff
with
add
turning the command into
git add -- file1.txt file2.txt
without having to retype the entire command.