Please share your BSD Tips and Tricks and we can publish a selection of them on the aggregator page: https://www.moritz.systems/bsd-tips-and-tricks/ Enjoy!

"Find the largest files in the current directory" by Kamil Rytarowski ``` find . -type f -exec stat -f "%z %N" {} \; | sort -r -n -k1 ``` https://www.moritz.systems/bsd-tips-and-tricks/find-largest-files-in-the-current-directory/ #FreeBSD #NetBSD #OpenBSD

@"kamil"#178 ...and with some eye-candy ;) [img]https://i.postimg.cc/zv5Y5B8D/2020-11-09-164728-1366x768-scrot.png[/img] I'm really liking this `broot` tool.

EDIT: removed stray `;` in the `c` function. @"kamil"#p5118 3 selections: 1. Remove duplicate lines in files (eg. rc.conf files, shell history files): ```sh $ cat ~/bin/nuniq.sh #!/bin/sh # # nuniq.sh: Remove duplicate lines, leaving only the last one. # (based on histsort.awk from "GAWK: Effective AWK Programming") exec awk ' { lines[NR] = $0 if ($0 in array) delete lines[array[$0]] array[$0] = NR } END { for (i = 1; i

To reduce the cycle of asking people for permission. Pasting here the tips and tricks means that I can publish them on the website freely, without asking and with the credit for submitter.

A tip which is trivial, but overlooked: Use -C to specify the directory in which `make` should run, as in: ``` make -C /usr/pkgsrc/devel/git-base install clean clean-depends ```

### MVMPIYTGA! Make viewing man pages in your terminal great again! `alias man='w3mman'`

@"rvp"#p5125 Is this form OK: `alias clr='printf "\033[H\033[J"'` ? I needed to delete the semicolon character as otherwise it was printed in the termnial (NetBSD, ksh).

@"[unknown]"#p5136 Use `clear` instead of hardcoding the sequence to stay terminal independent. If you need it multiple times and don't want to call en external binary each time: ``` $ CLEAR=$(clear) # or tput clear $ printf "$CLEAR" | hexdump -c 0000000 033 [ H 033 [ J 0000006 ```

> @"kamil"#p5136 I needed to delete the semicolon character I swear that wasn't there when I typed it in. It's these semicolons I tell you--they sneak right in somehow. Thank you for eradicating the beast. I made the `clear` work-alike a function because a) I prefer functions, and b) some shells don't have an `alias` command. However, `alias` is in POSIX, so go right ahead with them. As for permissions, etc: All code/scripts I write and post on this board can be considered to be in the public-domain. Use as you wish. Code & scripts I did not write, I will try to attribute correctly, and for these, you'll have to use your own judgement. Some sed(1) one-liners: 1. The sed(1) "list" command is very useful when dealing with unprintable (and invisible!) chars. I use it all the time because the other methods of dealing with these pesky characters is not very convenient: hexdump(1) is great, but, it doesn't preserve line endings; and vis(1) is a BSD-only thing. ```sh $ printf 'MS-DOS line ending\r\n' | sed -n l MS-DOS line ending\r$ $ printf 'Non-breaking space: '$'\u00A0''\n' | LC_ALL=C sed -n l Non-breaking space: \302\240$ ``` 2. Insert thousands-separators into numbers. The `-h` option to commands like du(1), df(1), etc. are nice and all, but, sometimes I want to see whole numbers in outputs. Then separators are useful to make sense of large numbers. ```sh #!/usr/bin/sed -Ef # # Insert US-style thousands-separators (commas) into numbers. : loop s/(^|[[:blank:]]+)([0-9]{1,})([0-9]{3})([0-9,]*)([[:blank:]]+|$)/\1\2,\3\4\5/ t loop ``` Use as: `du -a /some/dir | comma`, or `netstat -b -w 1 -I alc0 | comma`, etc. 3. Number lines in file. ```sh #!/bin/sh # # Simulate nl(1) or cat(1) -n exec sed -e = -- ${1+"$1"} | sed -nEe 'N;s/([[:digit:]]+)./\1'$'\t''/;p' ``` 4. NetBSD doesn't come with a tree(1) command so here's one in sed(1): ```sh #!/bin/sh # # Print directory tree exec find -- ${1:-.} | sed -Ee '2,$s:[^/]*/: :g; s: ([^ ]+)$:|_ \1:' ``` Note: it doesn't draw a fully-connected tree. Drawing a full tree is very hairy--and, completely out of our self-imposed one-liners category. 5. Reverse-print a file--aka tac(1): ```sh #!/bin/sh # # Implement tac(1) using sed(1). exec sed -ne '1h; 2,${x;H;}; ${x;p;}' -- "$@" ``` 6. Same thing in ed(1); using the standard idiom: ```sh #!/bin/sh # # Implement tac(1) using ed(1). : ${1?"Usage: ${0##*/} FILE"} exec ed -s -- "$1"

> @"qik"#p5133 A tip which is trivial, but overlooked: Use -C to specify the directory in which make should run Yes, just like `patch -d /some/dir ...`

Moritz Systems | BSD Tips and Tricks

rvp

Remove duplicate and nonexistent directories from PATH

#!/usr/bin/awk -f
#
# Remove duplicate and nonexistent directories from PATH
#
# Dir. names must not contain newlines or `:'; everything 
# else should be OK.
#
# Usage: export PATH="$(repath "$PATH")" (sh)  OR
#        export PATH="$(repath)"               OR
#        setenv PATH "`repath "$PATH"`"  (csh) OR
#        setenv PATH "`repath`"

# Quote `arg' for shell
function q(arg, s)
{
	s = arg
	gsub(/'/, "'\\''", s)	# first, turn every ' -> '\''
	return "'"s"'"		# then, single-quote the whole thing
}
BEGIN {
	path = ARGC == 2 ? ARGV[1] : ENVIRON["PATH"]
	sep = ":"
	n = split(path, P, sep)
	for (i = 1; i <= n; i++) {
		dir = P[i] == "" ? "." : P[i]
		if (H[dir]++ == 0 &&
		    system(sprintf("test -d %s", q(dir))) == 0)
			printf("%s%s", c++ == 0 ? "" : sep, dir)
	}
	if (c) printf("\n");
}

To use this script, put something like this towards the end of your ~/.profile or ~/.shrc--after all PATHs have been set:

export PATH="$(repath "$PATH")"

csh users should use this in their ~/.login or ~/.cshrc files:

setenv PATH "`repath "$PATH"`"

JuvenalUrbino

Script to set up a user-owned tmp directory with restricted access. Good to be sourced inside .xinitrc | .xsession

#!/bin/sh
USER=$(whoami)
GROUP=$(id -ng $USER)
mkdir /tmp/${USER}-runtime 
chown $USER:$GROUP /tmp/${USER}-runtime
chmod -R 0700 /tmp/${USER}-runtime
XDG_RUNTIME_DIR=/tmp/${USER}-runtime; export XDG_RUNTIME_DIR

Script to create temporary user cache on volatile memory.

# Check if ~/.cache is a symbolic link to a directory owned by the user.
# If the link's target is not a directory or does not exist, create a
# directory owned by the user under /tmp, and make ~/.cache a symbolic
# link to it.
#
uid=$(id -u)
if [ -L ~/.cache ]; then
	if [ -d ~/.cache ]; then
		ownerid=$(stat -L -f %u ~/.cache)
		if [ "${ownerid}" != "${uid}" ]; then
			recreate_cache=1
		fi
	else
		recreate_cache=1
	fi
	if [ "${recreate_cache}" = "1" ]; then
		user=$(whoami)
		unlink ~/.cache
		cachedir=$(mktemp -d /tmp/${user}.XXXXXX)
		ln -s ${cachedir} ~/.cache
	fi
fi

rvp

JuvenalUrbino This is pretty much what I do on OpenBSD for $XDG_RUNTIME_DIR--except that I use install.

JuvenalUrbino

Small script to quickly get a list of onboard PCI devices names and IDs

/usr/sbin/pcictl pci0 list \
 | awk -F: '{print "pcictl pci0 dump -b "$1" -d "$2}' \
 | sort -u| sh | grep -i 'device name' | cut -d ':' -f 2

On action:

thinkpad_R51:~ $ ids                                                                                            

 82855GM Host-Hub Controller (0x3580)
 82855GM GMCH Integrated Graphics Device (0x3582)
 82801DB USB UHCI Controller (0x24c2)
 82801BAM Hub-PCI Bridge (0x2448)
 82801DB LPC Interface Bridge (0x24cc)
 PCI1510 PCI-CardBus Bridge (0xac56)
 PRO/Wireless LAN 2200BG Mini-PCI Adapter (0x4220)

kamil

leave(1) - remind you when you have to leave

$ leave +0001
Alarm set for Mon Jan 25 21:16. (pid 6979)
Just one more minute!
$

One minute later…

$ Time to leave!

https://www.moritz.systems/bsd-tips-and-tricks/leave/

rvp

kamil Another golden oldie: lock - lock the current terminal until password is input

$ lock -np
lock: /dev/pts/3 on x202e.localdomain.  no timeout.
time now is Mon Jan 25 23:51:20 UTC 2021
Password:

Input password to unlock, or use only -p for a 15 min. timeout.

rvp

JuvenalUrbino Some useful X settings:

Very nice--I use most of 'em myself.

kamil leave(1) - remind you when you have to leave

I'm not saying leave is not useful--glad that some folks still remember it exists, but, I prefer at for this. It's specified by POSIX; you can enter arbitrary commands; you can log off the original terminal you set it on--or even reboot--and come back elsewhere and it'll still email you; you can queue multiple reminders:

$ at 19:30
echo 'Enough! Time to go home.'
Ctrl-D
Job 87 will be executed using /bin/sh
$ atq
Date                 Owner              Queue    Job
19:00:00 2021-01-31  rvp                c        87
$

JuvenalUrbino

Some useful X settings:

xset s off                                  # disable saver (using xlock) 
xset +dpms                                  # powersaving
xset dpms 1200 1500 1800                    # screen blanking
xset b 0                                    # mute bell
xset m 55/20 4                              # mouse acceleration 
xset r rate 250 40                          # faster keypresses
xset +fp  ${HOME}/.local/share/fonts/       # user fontpath
xhost +local:root > /dev/null 2>&1          # privileged X server access 
xsetroot -cursor_name top_left_arrow        # left pointer as cursor
xsetroot -mod 16 16 -fg steelblue -bg black # grid background 
setxkbmap -model pc105 -layout "it,us" -option terminate:ctrl_alt_bksp

yeti

rvp ...alternatively to the rude ctrl-d:

~$ at 22:02 << endat
> echo moo
> endat
commands will be executed using /bin/ksh
job 1612130520.c at Sun Jan 31 22:02:00 2021

rvp

yeti ...alternatively to the rude ctrl-d:

Even better is: at -f script TIME or at TIME < script--the latter is how I generally run it. 😉

rvp

Take a screenshot the easy way:

Almost everybody has a movie player installed these days, and that movie player will usually bring in the ffmpeg package. Therefore, I take my screenshots like this:

$ ffmpeg -loglevel fatal -f x11grab -i :0 -frames:v 1 ss.png

Blam!
(Change the extension to .jpg and ffmpeg will obligingly output a JPEG file.)

pfr

rvp Trying to get the output as the date format with
$ ffmpeg -loglevel fatal -f x11grab -i :0 -frames:v 1"$(echo $(date +'%d-%m-%Y.%H:%M'))".png but this doesn't work... what am I doing wrong here?

rvp

pfr That echo bit is redundant as date allows arbitrary text in the format string. Try this:

$ ffmpeg -loglevel fatal -f x11grab -i :0 -frames:v 1 "$(date +"ss-%d-%m-%Y--%H.%M.%S.png")"

ffmpeg doesn't like : in the output filename.

pfr

rvp Cheers. So many ways of taking a screenshot... who knew 🤔

pfr

@kamil
This should probably be credited to @rvp although I did originally find it on youtube related to zsh (although I cant seem to find it again).

alias h='fc -l 1 | awk "{ sub(/^[[:blank:]]*[0-9]+[[:blank:]]+/, \"\"); print }" | fzf | tr -d "\n" | xclip -selection c'

Requires fzf but is a great way to search your ksh history and copy previous commands to the clipboard,

rvp

pfr If you're going to recommend that pipeline, please use the simpler one which uses fc -n and sed. That awk regex is just too much--what was I thinking!

pfr

rvp My bad, I didn't notice you had corrected your post to use sed instead of awk so I'm yet to try that.

rvp

Remove shell-style comments and empty/blank lines for display

#!/bin/sh
#
# nocom.sh: Display only non-blank non-commented lines.

exec sed -Ee '
/^#!\//b
/^[[:blank:]]*(#|$)/d' -- "$@"

Useful for exmining shell-scripts, config. files, etc. without the intervening clutter.

$ diff -u <(nocom.sh /etc/rc.conf.orig) <(nocom.sh /etc/rc.conf)

rvp

Use `sed` to split a single patch file into multiple ones using line numbers

Let's say you have a patch file like this one and you want to split it into multiple patch files for some reason. This is easily done using sed:

First, determine the line numbers. For a unified diff like the above:

$ grep -n -- '^diff ' ~/tmp/ueberzug-18.1.9.patch
1:diff -urN ueberzug-18.1.9.orig/Xshm/Xshm.c ueberzug-18.1.9/Xshm/Xshm.c
22:diff -urN ueberzug-18.1.9.orig/examples/fzfimg.sh ueberzug-18.1.9/examples/fzfimg.sh
34:diff -urN ueberzug-18.1.9.orig/ueberzug/query_windows.py ueberzug-18.1.9/ueberzug/query_windows.py
55:diff -urN ueberzug-18.1.9.orig/ueberzug/xutil.py ueberzug-18.1.9/ueberzug/xutil.py
$

Now, you can sed to split that patch into 3 or 4 pieces (depending on whether you want a patch for each directory, or one for each file, respectively):

$ sed -n \
    '1,21w 1.patch
     22,33w 2.patch
     34,54w 3.patch
     55,$w 4.patch' \
    ~/tmp/ueberzug-18.1.9.patch
$ ls
1.patch  2.patch  3.patch  4.patch
$

rvp

Shell as interactive line-editor

If you're in a tight spot with no editor close by (or don't want to use the standard ones like ed(1) or vi(1)), you can use the shell's own line-editing features to create a file line-by-line (make sure you quote things correctly for your shell):

Using echo(1):

$ set -o emacs						# EMACS-like line-editing
$ echo 'test \! -r /etc/mk.conf'          > x.sh	# 1st line
$ echo 'test \! -r /etc/pkg_install.conf' >> x.sh	# 2nd line: up-arrow; edit
...							# many lines later...
$ chmod u+x x.sh

This is the simplest method.

Using cat(1) and here-docs:

$ set -o emacs					# EMACS mode
$ cat > x.sh <<\EoF				# read until an `EoF'
> test \! -r /etc/mk.conf			# 1st line
> test \! -r /etc/pkg_install.conf		# 2nd line: up-arrow; edit
...
> EoF						# done with here-doc
$ chmod u+x x.sh

The problem with this is that every up-arrow bring in all the previously entered lines. So we come to, my preference, #3:

Using exec:

$ sh						# spawn new shell first
$ set -o emacs					# EMACS mode
$ exec > x.sh					# redirect all output to file
$ echo 'test \! -r /etc/mk.conf'		# 1st line
						#   Note that no output is seen
						#   because it all goes into the
						#   file
$ echo 'test \! -r /etc/pkg_install.conf'	# 2nd line: up-arrow; edit
...
$ <Ctrl-D>					# exit "editor" shell
$ chmod u+x x.sh

JuvenalUrbino

rvp Possible alternative one line solutions for very short files:

$ { echo 'test \! -r /etc/mk.conf' ; echo 'test \! -r /etc/mk.conf'; } >> x.sh          # using echo
$ printf '%s\n%s\n' 'test \! -r /etc/mk.conf'  'test \! -r /etc/mk.conf' >> x.sh        # using printf

I find printf particularly useful for introducing tab spaces; so for example, I often find myself using:

$ printf '%s\n\t%s\n' 'test \! -r /etc/mk.conf'  'test \! -r /etc/mk.conf' >> x.sh

which results in:

test \! -r /etc/mk.conf
    test \! -r /etc/mk.conf

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