Post your handy self made command line utilities

Trilby · 2021-03-10 15:48:16

seth wrote:

... and get Trilby a cardiac arrest

No worries. Scripts that involved to do something so trivial don't even get read, though my thoughts on the whole thing can be summed up by the license name with a little formating:

while true; DO
   WHAT THE FUCK?
done

read -p "YOU WANT TO PUBLIC LICENSE?" response

Once you break out of the loop, you'll want to respond "no" at the prompt

Awebb · 2021-04-16 12:13:39

Until I find some satisfying solution for the lack of Google sync stuff in Chromium, I have installed google-chrome from the AUR. The maintainers seem to be rather quick, but I don't want to bet on that. The Idea: If extra/chromium is newer than google-chrome on the AUR, then I want to know that.

It requires expac and either auracle or jq. It comes with a rudimentary hook.

chromcheck:

#!/bin/bash

if ! pacman -Qq google-chrome 2>/dev/null 1>/dev/null; then
        echo "NOTE: google-chrome not installed. Nothing to do."
        exit 0 # not having google-chrome is fine
fi
if pacman -Qq expac 2>/dev/null 1>/dev/null; then
        chrome_query="$(expac -Q %v google-chrome | sed "s/-[0-9]*//")"
        chromium_sync="$(expac -S %v chromium     | sed "s/-[0-9]*//")"
else
        echo "ERROR: expac is required"
        exit 1
fi
if pacman -Qq auracle-git 2>/dev/null 1>/dev/null; then
        chrome_aur="$(auracle info google-chrome | grep Version | sed "s/.* : //" | sed "s/-[0-9].*//")"
elif pacman -Qq curl jq 2>/dev/null 1>/dev/null; then
        chrome_aur="$(curl -s 'https://aur.archlinux.org/rpc.php/?v=5&type=info&arg[]=google-chrome' | jq -r .results[].Version | sed "s/-[0-9]*//")"
else
        echo "ERROR: Either auracle or both curl and jq must be installed."
        exit
fi

if [[ ! "$chrome_query" == "$chromium_sync" ]]; then
        echo "local/Chrome: $chrome_query"
        echo "extra/Chromium: $chromium_sync"
        echo "aur/Chrome: $chrome_aur"
fi

chromcheck.hook

[Trigger]
Operation = Upgrade
Type = Package
Target = *

[Action]
Description = compare local/google-chrome with extra/chromium and inform about the AUR version 
When = PostTransaction
Exec = /usr/local/bin/chromcheck

Any comments besides "learn awk to avoid grep|sed|sed"?

EDIT: The hook works! My first hook.
EDIT: Found a typo. It's fine in the script, wonder what happened during copy-paste.
EDIT: Ok, let's see how many errors I can find myself. Why was this even working?
EDIT: Hopefully the final version. It now checks for auracle and if that's not there, it falls back to curl + jq.

Last edited by Awebb (2021-04-16 16:33:54)

Flemur · 2021-04-16 12:51:46

I use a terminal far more often than any menus, and use this 'W' script pretty often.

W = find files in $PATH given part of the name, w/optional grep. ('W' is from 'which'...)

$ cat bin/W

#!/bin/bash
# Find files in $PATH matching *$1* [| grep -i $2]
#
if [ $# -lt 1 ]
then
  echo Usage: `basename $0` pattern  [ pattern2 ]
  exit 1
fi 

if [ $# -eq 1 ]; then
  echo $PATH | sed 's/^/ls -A /' | sed 's/:/ |grep -i '$1'; ls -A /g' | sed 's/$/ |grep -i '$1'/' | bash | sort 
  exit 0
fi 

if [ $# -eq 2 ]; then
  echo $PATH | sed 's/^/ls -A /' | sed 's/:/ |grep -i '$1'; ls -A /g' | sed 's/$/ |grep -i '$1'/' | bash | sort  | grep -i $2
  exit 0
fi

$ W player
Flashplayer
cdda-player
mplayer
smplayer
$
$ W player m
mplayer
smplayer

Trilby · 2021-04-16 12:55:10

Awebb wrote:

Any comments besides "learn awk to avoid grep|sed|sed"?

Well ... learn sed to avoid grep|sed|sed

... | sed -n '/Version/{s/.* : //;s/-[0-9].*//;p}'

But the pipelines in Flemur's "W" are a bit more ... in need a single regex search can just be this:

IFS=:; find $PATH -iname "*$1*" -exec basename '{}' \;

Multiple:

IFS=:; find $PATH -iname "*$1*" -iname "*$2*" -exec basename '{}' \;

No pipelines needed at all, and certainly no need to parse `ls` output. In fact, the whole thing should be able to be just this:

#!/bin/sh

IFS=:; eval find $PATH $(printf ' -iname "*%s*"' $@) -exec basename "'{}' \;"

Last edited by Trilby (2021-04-16 13:32:36)

Flemur · 2021-04-16 15:10:18

Trilby wrote:

In fact, the whole thing should be able to be just this:
#!/bin/sh

IFS=:; eval find $PATH $(printf ' -iname "*%s*"' $@) -exec basename "'{}' \;"

Cool! I don't understand it, but I no longer understood mine either, not long after making it.

Awebb · 2021-04-16 15:16:19

Trilby wrote:

Awebb wrote:
Any comments besides "learn awk to avoid grep|sed|sed"?
Well ... learn sed to avoid grep|sed|sed
... | sed -n '/Version/{s/.* : //;s/-[0-9].*//;p}'

That seems to be my recurring theme :-D

Trilby · 2021-04-16 15:33:48

Flemur wrote:

Cool! I don't understand it, but I no longer understood mine either, not long after making it.

The combined version with the 'eval' is admittedly a bit awkward. What's the line about 'eval' being a misspelling of 'evil'? But it's the cleanest way I thought of to include any number (greater than zero) of patterns to match. Hopefully the separate versions for one or two patterns would be understandable:

IFS=:

This is just so we can pass $PATH to find as the location(s) to search (IFS is the Input Field Separator variable, and $PATH includes paths separated by a ':'). I think you could instead do something like this for similar effect:

find $(echo $PATH | tr ':' ' ') ...

Then we use the "-iname" flag for find so it matches file names case insensitively against "*$1*", the asterisks so that $1 can appear anywhere in the filename and still match. Then it ends with find's "-exec" flag which runs a certain command on each result. Here we use 'basename' on each result to get the ... basename. You can see the result without this is still valid, just not as pretty:

IFS=:; find $PATH -iname "*$1*"

This will produce the same results, but each one will include the full path.

In reality, you may want to include another flag to find like "-executable" to limit results to files that are executable. I'm not sure if there should be any nonexecutable content in $PATH locations, but it's certainly possible, and you wouldn't want those files listed.

Last edited by Trilby (2021-04-16 15:34:49)

Awebb · 2021-04-16 16:35:28

I've fixed my script. Still a lot of piping, but that'll be homework for another day.

Flemur · 2021-04-16 16:41:48

Trilby wrote:

IFS=:; find $PATH -iname "*$1*"
This will produce the same results, but each one will include the full path.

Hey, thanks!, that's what I usually prefer (sometimes the same name is in more than one place, etc) so I changed my W to

#!/bin/sh
# from Trilby, Arch forums
# IFS=:; find $PATH -iname "*$1*" -iname "*$2*" -exec basename '{}' \;
IFS=:
eval find $PATH $(printf ' -iname "*%s*"' $@)

As a side benefit it now works with a bunch of arguments (Edit: with no args it lists all the files in $PATH):

$ W la p r m y
/usr/bin/mplayer
/usr/bin/smplayer

Last edited by Flemur (2021-04-16 16:54:56)

Awebb · 2021-04-16 16:44:49

@Flemur: This reminds me a bit of dmenu_run from the dmenu package.

schard · 2021-04-16 22:54:10

I wrote myself an emergency reboot program that can be used to forcibly reboot a system using Sysrq if the internal disk produces I/O errors due to file system issues and the system cannot be rebooted otherwise [1]:
Needless to say, that you should not use this for a reboot during normal operations, since it will result in data loss.
I use it with the suid bit set (since all users on the target systems are trusted) and added it to the initramfs BINARIES=().

er.c

/**
  er.c - Emergency reboot: Reboot a Linux system using sysrq.

  (C) 2021 Richard Neumann <mail at richard dash neumann period de>

  This program is free software: you can redistribute it and/or modify
  it under the terms of the GNU General Public License as published by
  the Free Software Foundation, either version 3 of the License, or
  (at your option) any later version.

  This library is distributed in the hope that it will be useful,
  but WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  GNU General Public License for more details.

  You should have received a copy of the GNU General Public License
  along with this library.  If not, see <http://www.gnu.org/licenses/>.

  Note:
	The compiled binary must have the suid bit set
	in order to work for an arbitrary user.
*/
#include <errno.h>
#include <stdio.h>

int write_to_file(char* filename, char* value)
{
	int rc;
	FILE *fp;

	fp = fopen(filename, "w");
	if (fp == NULL)
		return -EIO;

	rc = fprintf(fp, value);
	fclose(fp);
	return rc;
}

int main()
{
	int rc;

	rc = write_to_file("/proc/sys/kernel/sysrq", "1");
	if (rc > 0)
		rc = write_to_file("/proc/sysrq-trigger", "b");
	if (rc > 0)
		return 0;

	return rc;
}

[1] Current scenario that triggered the development:

$ ssh 1120.terminals.homeinfo.intra /bin/sh

sudo systemctl reboot
/bin/sh: line 2: /usr/bin/sudo: Input/output error
reboot
Failed to set wall message, ignoring: Access denied
Failed to reboot system via logind: Access denied
Failed to talk to init daemon.
su
/bin/sh: line 4: /usr/bin/su: Input/output error
su -c reboot
/bin/sh: line 5: /usr/bin/su: Input/output error

Last edited by schard (2021-04-16 22:55:18)

respiranto · 2021-04-17 21:30:06

Trilby wrote:

#!/bin/sh

IFS=:; eval find $PATH $(printf ' -iname "*%s*"' $@) -exec basename "'{}' \;"

I'd suggest escaping $PATH and quoting $@ to allow for whitespace in them.
Also, find has `basename' built in.

IFS=:; eval find \$PATH $(printf ' -iname "*%s*"' "$@") -printf '%f\\n'

Trilby · 2021-04-18 01:52:38

Yes, $@ should be quoted - though I'd certainly not have any executables in my PATH with spaces in their names. As for find's -printf flag, that will work on most arch systems, but it is a GNU extension to 'find' (it only works on my system with /bin/find). I don't see the purpose in escaping PATH. Can you elaborate on that?

eschwartz · 2021-04-18 05:22:28

Awebb wrote:

Until I find some satisfying solution for the lack of Google sync stuff in Chromium, I have installed google-chrome from the AUR. The maintainers seem to be rather quick, but I don't want to bet on that. The Idea: If extra/chromium is newer than google-chrome on the AUR, then I want to know that.

You could try using a decent web browser, I suppose.

respiranto · 2021-04-18 11:16:34

Trilby wrote:

As for find's -printf flag, that will work on most arch systems, but it is a GNU extension to 'find' (it only works on my system with /bin/find).

I far too often forget that the GNU tools are non-standard.

I just noted that `basename' was quite slow for a larger number of files (i.e., calls). Fortunately, basename has a `-m' flag to allow for multiple arguments. Oh wait, that's a GNU extension.

Trilby wrote:

I don't see the purpose in escaping PATH. Can you elaborate on that?

If $PATH is unescaped, it is expanded (including word-splitting on `:') before `eval' is called. `eval' then concatenates the words resulting from expansion, separated by whitespace. In particular, whitespace present in $PATH is now indistinguishible from whitespace originating from `:'. The result is finally regularly evaluated, as if it was passed to `sh -c'.

A simplified demonstration (ve: variable expansion, ee: `eval' evaluation):

$ VAR='1:2 3'
$ IFS=:
$ eval printf 'a:%s\\n' $VAR
ve-> eval printf 'a:%s\\n' 1 '2 3'
ee-> printf a:%s\\n 1 2 3
> a:1
> a:2
> a:3
$ eval printf 'b:%s\\n' \$VAR
ee-> printf b:%s\\n $VAR
ve-> printf b:%s\\n 1 '2 3'
> b:1
> b:2 3

To get more unexpected results, consider VAR='1 "2:3"' or VAR='$(rain)'.

Last edited by respiranto (2021-04-18 13:11:36)

Awebb · 2021-04-18 12:59:59

eschwartz wrote:

Awebb wrote:
Until I find some satisfying solution for the lack of Google sync stuff in Chromium, I have installed google-chrome from the AUR. The maintainers seem to be rather quick, but I don't want to bet on that. The Idea: If extra/chromium is newer than google-chrome on the AUR, then I want to know that.
You could try using a decent web browser, I suppose.

That would be fantastic, but as long as I'm hopping between 5+ devices and three operating systems, Chrome's sync and some Keepass offspring have so far been the only solution that isn't a maintenance nightmare. Firefox' sync doesn't work reliably on Android (at least for me), but that's where a good half of my web usage happens.

Trilby · 2021-04-18 13:06:08

respiranto wrote:

In particular, whitespace present in $PATH is now indistinguishible from whitespace originating from `:'.

Very true. Thanks. I suppose my bias (or good habit) shows in that spaces in executables in PATH is just something I'd avoid, spaces in components of PATH seem downright evil to me But it can happen and good code should cope with it.

(edit: typos, why the hell would I put apostrophes in plurals ... more coffee...)

Last edited by Trilby (2021-04-18 13:06:55)

schard · 2021-04-24 19:55:53

I wrote a script to list the contents of pacman databases as JSON for web applications.
It depends only on the standard library.

#! /usr/bin/env python3
# 
# pjdb.py - JSON-ify pacman databases.
#
# (C) 2021 Richard Neumann <mail at richard dash neumann period de>
# 
# This program is free software: you can redistribute it and/or modify  
# it under the terms of the GNU General Public License as published by  
# the Free Software Foundation, version 3.
#
# This program is distributed in the hope that it will be useful, but 
# WITHOUT ANY WARRANTY; without even the implied warranty of 
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 
# General Public License for more details.
#
# You should have received a copy of the GNU General Public License 
# along with this program. If not, see <http://www.gnu.org/licenses/>.

"""JSON-ify pacman database."""

from datetime import datetime
from json import dumps
from pathlib import Path
from subprocess import CompletedProcess, run
from sys import argv
from tempfile import TemporaryDirectory
from typing import Iterator, Union


DESCFILE = 'desc'
INT_KEYS = {'%BUILDDATE%', '%CSIZE%', '%ISIZE%'}
LIST_KEYS = {'%DEPENDS%', '%MAKEDEPENDS%', '%OPTDEPENDS%'}
LIST_SEP = '\n'
ITEM_SEP = '\n\n'
KEY_VALUE_SEP = '\n'
TAR = '/usr/bin/tar'
KeyValuePair = tuple[str, Union[str, int]]
PackageDescription = tuple[str, KeyValuePair]


def _tar_xf(tarfile: Path, directory: Path) -> CompletedProcess:
    """Workaround for missing zstd support in Python's tar library."""
    
    return run([TAR, 'xf', str(tarfile), '-C', str(directory)], check=True)


def kv_from_str(text: str) -> Iterator[KeyValuePair]:
    """Yields key / value pairs from a string."""

    for item in text.split(ITEM_SEP):
        if not item.strip():
            continue

        key, value = item.split(KEY_VALUE_SEP, maxsplit=1)

        if key in INT_KEYS:
            value = int(value)
        elif key in LIST_KEYS:
            value = value.split(LIST_SEP)

        yield (key.replace('%', '').lower(), value)


def kv_from_file(filename: Path) -> Iterator[KeyValuePair]:
    """Yields key / value pairs from a file."""
    
    with filename.open('r') as file:
        yield from kv_from_str(file.read())


def pkg_from_dir(dirname: Path) -> PackageDescription:
    """Reads package information from a package directory."""
    
    return (dirname.name, dict(kv_from_file(dirname / DESCFILE)))


def pkgs_from_dir(dirname: Path) -> Iterator[PackageDescription]:
    """Yields package descriptions."""
    
    for pkgdir in dirname.iterdir():
        yield pkg_from_dir(pkgdir)


def pkgs_from_db(filename: Path) -> Iterator[PackageDescription]:
    """Yields package descriptions from a database file."""

    with TemporaryDirectory() as tmpd:
        tmpd = Path(tmpd)
        _tar_xf(filename, tmpd)
        yield from pkgs_from_dir(tmpd)


def main():
    """Test the above stuff."""
    
    databases = {}

    for database in argv[1:]:
        databases[database] = dict(pkgs_from_db(database))
        
    print(dumps(databases, indent=2))


if __name__ == '__main__':
    main()

Awebb · 2021-04-24 20:13:20

Awebb wrote:

Until I find some satisfying solution for the lack of Google sync stuff in Chromium, I have installed google-chrome from the AUR. The maintainers seem to be rather quick, but I don't want to bet on that. The Idea: If extra/chromium is newer than google-chrome on the AUR, then I want to know that.

To my surprise, google-chrome on the AUR got updated faster than chromium in the repos. Oh well, now I need a new non-issue to fix.

MangoMan1 · 2021-04-29 14:30:12

First post here on the forums. Here are 3 command line tools I wrote that I find myself using every once in a while. I'll just link the github urls to not post a massive wall of C.

$ pp "[LINE] " </some/file  # Prepend text
[LINE] Some text
[LINE] Some more text
$ ap . </another/file  # Append text
This file had no periods.
I like having periods.
$ cal | center - .gitignore
                                                                                April 2021
                                                                           Mo Tu We Th Fr Sa Su
                                                                                     1  2  3  4
                                                                            5  6  7  8  9 10 11
                                                                           12 13 14 15 16 17 18
                                                                           19 20 21 22 23 24 25
                                                                           26 27 28 29 30

                                                       # https://www.gutenberg.org/ has lots of material to test on.
                                                                                   test/
                                                                                    *.o
                                                                                __mbuild.sh
                                                                               .clang-format
                                                                                  center
$

pp/ap
center

Trilby · 2021-04-29 14:53:31

Why ap/pp and not just sed?

sed 's/^/[LINE] /' /some/file
sed 's/$/./' /another/file

MangoMan1 · 2021-04-29 16:29:53

Trilby wrote:

Why ap/pp and not just sed?
sed 's/^/[LINE] /' /some/file
sed 's/$/./' /another/file

I originally made pp both because I had some free time and nothing to do, and for the same reason I use `grep 'regex'` to match lines instead of `awk '/regex/'`. That being that why use a much more complex tool for something when I can have a much simpler one to do it instead. I obviously don't do that for everything, but I was prepending text in a couple of places so I thought "why not?". As for ap, that came about simply because I already made pp, and it only required a few extra lines of code to adapt it.

lenhuppe · 2021-05-08 12:12:24

Until the current issue with the Spotify download servers is resolved I created this script to install/update Spotify.

spotify_workaround

#!/usr/bin/env bash

set -e

#
# print messages in bold
#
function print {
  echo -e '\n\t\033[1m' $1 '\033[0m\n'
}

#
# verify userid
#
if [ "$(whoami)" == "root" ] ; then
    print "run this script as a user with sudo access because makepkg cannot be run as root"
    exit
fi

#
# build spotify
#
curl -s https://download.spotify.com/debian/pubkey_0D811D58.gpg | gpg --import -
cd /tmp ; git clone https://aur.archlinux.org/spotify.git
cd spotify
echo "DLAGENTS=("http::/usr/bin/wget -r -np -nd -H %u")" >> PKGBUILD
makepkg --noconfirm -si && print "Spotify client setup complete"

Last edited by lenhuppe (2021-05-08 12:13:33)

lenhuppe · 2021-05-08 12:24:17

The iscan-plugin-perfection-v370 package has an issue with checksums. I created this script to install the package and use my Epson scanner.

iscan_workaround

#!/usr/bin/env bash

set -e

#
# print messages in bold
#
function print {
  echo -e '\n\t\033[1m' $1 '\033[0m\n'
}

#
# verify userid
#
if [ "$(whoami)" == "root" ] ; then
    print "run this script as a user with sudo access because makepkg cannot be run as root"
    exit
fi

#
# iscan-plugin-perfection-v370
#
print "Building epson scanner driver and utility"
cd /tmp ; git clone https://aur.archlinux.org/iscan-plugin-perfection-v370.git
cd iscan-plugin-perfection-v370
sed -i "s/sha256sums=('08026cedf7b13895526b5b6267e98f1ab2c5ed9eb417c565ef37cfd4787b7b65')/sha256sums=('7b44da1637432717aa2a2f7fd7dfbb04bcf486310484ce1c0a63ef5cb9968a32')/" PKGBUILD
makepkg --noconfirm -si && print "Image Scan for Epson setup complete"

dmz · 2021-05-08 12:36:59

I am using three monitors in a setup like this: [][ ][].
Works wonders, except when I want to play Spelunky. The 165hz refresh rate on the middle monitor is reduced to 60 because the side monitors are locked to 60. This script toggles those two monitors so I can play properly, and once I am done I press a button on the keyboard and it's restored again.

#!/bin/sh
# vim:ft=sh:
# toggle side panels in [][ ][] monitor setup

WIDTH=$(xrandr|grep -Po 'current.+, '|perl -pe 's/\w+\s(\d+) x.+$/$1/')

 MONITOR_LEFT='--off'
MONITOR_RIGHT='--off'

if [ $WIDTH -eq 1920 ]; # side panels disabled
  then
     MONITOR_LEFT='--rotate left --right-of DP-4 --auto'
    MONITOR_RIGHT='--rotate right --left-of DP-4 --auto'
    xscreensaver -no-splash &
    $RATPOISON -c 'echo screensaver enabled.'
  else # disable side panels
     MONITOR_LEFT='--off'
    MONITOR_RIGHT='--off'
    killall xscreensaver
    $RATPOISON -c 'echo screensaver disabled.'
fi

xrandr  --output HDMI-0 $MONITOR_LEFT --output DP-2 $MONITOR_RIGHT
catpoison -c restart

Arch Linux

#3526 2021-03-10 15:48:16

Re: Post your handy self made command line utilities

#3527 2021-04-16 12:13:39

Re: Post your handy self made command line utilities

#3528 2021-04-16 12:51:46

Re: Post your handy self made command line utilities

#3529 2021-04-16 12:55:10

Re: Post your handy self made command line utilities

#3530 2021-04-16 15:10:18

Re: Post your handy self made command line utilities

#3531 2021-04-16 15:16:19

Re: Post your handy self made command line utilities

#3532 2021-04-16 15:33:48

Re: Post your handy self made command line utilities

#3533 2021-04-16 16:35:28

Re: Post your handy self made command line utilities

#3534 2021-04-16 16:41:48

Re: Post your handy self made command line utilities

#3535 2021-04-16 16:44:49

Re: Post your handy self made command line utilities

#3536 2021-04-16 22:54:10

Re: Post your handy self made command line utilities

#3537 2021-04-17 21:30:06

Re: Post your handy self made command line utilities

#3538 2021-04-18 01:52:38

Re: Post your handy self made command line utilities

#3539 2021-04-18 05:22:28

Re: Post your handy self made command line utilities

#3540 2021-04-18 11:16:34

Re: Post your handy self made command line utilities

#3541 2021-04-18 12:59:59

Re: Post your handy self made command line utilities

#3542 2021-04-18 13:06:08

Re: Post your handy self made command line utilities

#3543 2021-04-24 19:55:53

Re: Post your handy self made command line utilities

#3544 2021-04-24 20:13:20

Re: Post your handy self made command line utilities

#3545 2021-04-29 14:30:12

Re: Post your handy self made command line utilities

#3546 2021-04-29 14:53:31

Re: Post your handy self made command line utilities

#3547 2021-04-29 16:29:53

Re: Post your handy self made command line utilities

#3548 2021-05-08 12:12:24

Re: Post your handy self made command line utilities

#3549 2021-05-08 12:24:17

Re: Post your handy self made command line utilities

#3550 2021-05-08 12:36:59

Re: Post your handy self made command line utilities

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