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#3376 2020-05-25 01:39:30

salonkommunist
Member
From: Germany
Registered: 2020-02-18
Posts: 26

Re: Post your handy self made command line utilities

That was really helpful. Thank you guys!

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#3377 2020-05-26 09:04:49

jasonwryan
Anarchist
From: .nz
Registered: 2009-05-09
Posts: 29,049
Website

Re: Post your handy self made command line utilities

Been a while...

#!/usr/bin/bash
# Update mail certs

target="$HOME/.local/certs"
PS3='Select a host: '
options=("dom1" "dom2" "dom3")

select opt in "${options[@]}"
  do
    case "$opt" in
    dom1) domain="mail.dom1.com"
              name="one"
              break
              ;;
    dom2) domain="mail.dom2.com"
              name="two"
              break
              ;;
    dom3) domain="mail.dom3.com"
              name="three"
              break
              ;;
           *) printf "%s\n" "Invalid host"
              exit 1
              ;;
    esac
done

openssl s_client -connect "$domain":993 -showcerts 2>&1 < /dev/null |\
  awk '/BEGIN/,/END/{print}/END/{exit}' > "$target"/"$name".pem

# vim:set ts=2 sts=2 sw=2 et:

Arch + dwm   •   Mercurial repos  •   Surfraw

Registered Linux User #482438

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#3378 2020-05-29 20:59:13

salonkommunist
Member
From: Germany
Registered: 2020-02-18
Posts: 26

Re: Post your handy self made command line utilities

#!/bin/bash
wd="~/.scripts/feedgen"
for i in $(cat $wd/urls) ; do
    title=$(curl -s -L $i 2> /dev/null | grep -m 1 title | awk -F \> '{print $2}' | awk -F \< '{print $1}')
    test -z "$title" && continue
    feed=$(echo $title | sed 's/ //g')
    if !(find $wd -type d | grep -q $feed) ; then
        mkdir -p $wd/$feed
        w3m $i > $wd/$feed/$feed.stale || exit 1
        echo "<?xml version=\"1.0\" encoding=\"UTF-8\" ?>" >> $wd/$feed/$feed.xml
        echo "<rss version=\"2.0\">" >> $wd/$feed/$feed.xml
        echo "" >> $wd/$feed/$feed.xml
        echo "<channel>" >> $wd/$feed/$feed.xml
        echo "    <title>"$title"</title>" >> $wd/$feed/$feed.xml
        echo "    <description>Generated by feedgen.sh</description>" >> $wd/$feed/$feed.xml
        echo "    <link>"$i"</link>" >> $wd/$feed/$feed.xml
        echo "    <pubDate>"$(date '+%a, %d %b %Y %H:%M:%S %z')"</pubDate>" >> $wd/$feed/$feed.xml
        echo "" >> $wd/$feed/$feed.xml
        echo "    <item>" >> $wd/$feed/$feed.xml
        echo "        <title>Now tracking "$title"</title>" >> $wd/$feed/$feed.xml
        echo "        <description>Now tracking "$title"</description>" >> $wd/$feed/$feed.xml
        echo "        <link>"$i"</link>" >> $wd/$feed/$feed.xml
        echo "        <pubDate>"$(date '+%a, %d %b %Y %H:%M:%S %z')"</pubDate>" >> $wd/$feed/$feed.xml
        echo "    </item>" >> $wd/$feed/$feed.xml
        echo "" >> $wd/$feed/$feed.xml
        echo "</channel>" >> $wd/$feed/$feed.xml
        echo "</rss>" >> $wd/$feed/$feed.xml
    else
        w3m $i > $wd/$feed/$feed.fresh || exit 1
        change=$(diff $wd/$feed/$feed.stale $wd/$feed/$feed.fresh)
        if ! test -z "$change" ; then
            head -n -2 $wd/$feed/$feed.xml > $wd/$feed/$feed.xml.tmp
            mv $wd/$feed/$feed.xml.tmp $wd/$feed/$feed.xml
            echo "    <item>" >> $wd/$feed/$feed.xml
            echo "        <title>"$title" has changed!</title>" >> $wd/$feed/$feed.xml
            echo "        <description>"$change"</description>" >> $wd/$feed/$feed.xml
            echo "        <link>"$i"</link>" >> $wd/$feed/$feed.xml
            echo "        <pubDate>"$(date '+%a, %d %b %Y %H:%M:%S %z')"</pubDate>" >> $wd/$feed/$feed.xml
            echo "    </item>" >> $wd/$feed/$feed.xml
            echo "" >> $wd/$feed/$feed.xml
            echo "</channel>" >> $wd/$feed/$feed.xml
            echo "</rss>" >> $wd/$feed/$feed.xml
        fi
        mv $wd/$feed/$feed.fresh $wd/$feed/$feed.stale
    fi
done

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#3379 2020-06-01 03:38:54

eschwartz
Trusted User/Bug Wrangler
Registered: 2014-08-08
Posts: 3,683

Re: Post your handy self made command line utilities

for i in $(cat $wd/urls) ; do
    ...
done

Don't do this, for loops don't loop over lines, they loop over space-separated words -- instead use:

while IFS= read -r i ; do
    ...
done < $wd/urls
wd="~/.scripts/feedgen"
for i in $(cat $wd/urls) ; do

The $wd variable contains the literal text ~/ and this will resolve to the directory name ./\~/.scripts/feedgen which I doubt you want. Don't quote home directory tilde expansions. Better yet, use $HOME which gets expanded properly.

    title=$(curl -s -L $i 2> /dev/null | grep -m 1 title | awk -F \> '{print $2}' | awk -F \< '{print $1}')

This is a lot of chained commands for something awk is not very good at. I would recommend sed here:

    title=$(curl -s -L $i 2> /dev/null | sed -nr '/title/{s/.*>(.*?)<.*/\1/p;q}'

But in truth, you should use a real xml parser, like xmllint or xmlstarlet.


    if !(find $wd -type d | grep -q $feed) ; then

The !(...) is not needed here, simply use

    if ! find $wd -type d | grep -q $feed ; then

You don't need to run the find | grep pipeline inside an *additional* subshell, and it's not part of the grammar of the "if" keyword.

        change=$(diff $wd/$feed/$feed.stale $wd/$feed/$feed.fresh)
        if ! test -z "$change" ; then

Since you don't care about creating a patch file, but only wish to assert that the two files are different, consider using "cmp -s" instead of diff.

Last edited by eschwartz (2020-06-01 03:39:17)


Managing AUR repos The Right Way -- aurpublish (now a standalone tool)

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#3380 2020-07-04 07:37:48

assertion9
Member
Registered: 2019-04-13
Posts: 19

Re: Post your handy self made command line utilities

Performs full system backup with rsync tool in automated or user interacted ways. Invoked via system systemd timer in non-interactive shell. I will be glad to receive any criticism, since this is one of my first ever written shell script which takes more than 10 lines of code

Style issues I have found but didn't know how to fix:
1. Sciprt calculates two times backup_samples amount:
- at the start to check whether any sample exists to decrypt and unpack it
- in the function "remove_obsolete" after(if) new sample was successfully created
2. Don't know if this common practice, but I declared variable "latest" in function "check_first_run" and used it in "remove_obsolete" which perfectly worked but in other languages such usage would be impossible since variable "latest" would be inacessible for latter function "remove_obsolete"
3. Since script is invoked from non-interactive shell in "check_first_run" I have used some kind of a popup terminal window for receiving user password to decrypt latest gpg backup sample. Please, let me know if I could do this in any way better

PS1=Probably I should even cut out the whole part for checking existing samples of backup and don't unpack latest gpg file. Instead just store mirror of the whole system in "/var/tmp/data". Which in turn will drastically reduce time of backing up stuff, since I have a lot of media files such as audio/video/pictures and each time moving them with rsync and then compress already compressed formats of video/audio which will not result in any descension of total occupied size of backup sample seems like waste of energy

#!/bin/sh

recepient="assertion9@gmail.com"

dir="/var/tmp/fsbackup"
archive="/var/tmp/fsbackup/backup.tar.zst"
gpg_file="${dir:?}/$(date '+%I-%M%p_%d_%b_%Y').gpg"

MAX_BACKUP_SAMPLES=2
backup_samples=$(find "$dir" -maxdepth 1 -name "*.gpg" | wc -l)

dirs_skip_list="$dir /dev/ /proc/ /sys/ /tmp/ /run/ /mnt/"

get_user_input(){
    message=$1
    printf "%s\n" "$message"
    read -r answer
    if [ "$answer" != "${answer#[Yy]}" ]; then
        return 1
    else
        exit
    fi
}

remove_obsolete(){
    backup_samples=$(find "$dir" -maxdepth 1 -name "*.gpg" | wc -l)
    [ "$backup_samples" -ge "$MAX_BACKUP_SAMPLES" ] && rm -f "${oldest:?}"
}

check_first_run(){
    if [ -d "$dir" ] && [ "$backup_samples" -gt 0 ]; then
        samples="$(find /var/tmp/fsbackup -maxdepth 1 -type f -printf '%T+ %p\n' | sort | awk '{printf $NF " "}' | sed 's/.$//')"
        latest=${samples##* }
        oldest=${samples%% *}
        urxvt -name popup -e dash -c "gpg --homedir=/home/assertion9/.local/share/gnupg -o $archive -d $latest"
        if [ -f "$archive" ];then
            tar --zstd -xf "$archive"
            rm "$archive"
        else
            su assertion9 -c 'dunstify -u critical -i luckybackup "Bad passphrase! Backup aborted!"'
            exit 1
        fi
    else
        mkdir "$dir"
        chmod 700 "$dir"
    fi
}

backup(){
    src="/"
    dest="/var/tmp/fsbackup/data"
    msg="The full system backup will be created at $dir as a file $gpg_file. Proceed? (y/n)"

    [ "$1" != "auto" ] && get_user_input "$msg"

    su assertion9 -c 'dunstify -u critical -i luckybackup "Starting system backup..."'

    check_first_run

    exclude="$(printf ' --exclude=%s' $dirs_skip_list)"

    rsync -aAX --delete $exclude "$src" "$dest"

    tar --zstd -cf "$archive" "$dest"

    gpg --homedir=/home/assertion9/.local/share/gnupg -o "$gpg_file" -e -r "$recepient" "$archive"

    rm -rf "$dest" "$archive"

    remove_obsolete

    su assertion9 -c 'dunstify -u critical -i luckybackup "System backup finished!"'
}

restore(){
    msg="System will restore data from '$dest' to '/'. Proceed? (y/n)"

    get_user_input "$msg"

    while :
    do
        printf "Enter absolute path of gpg file: "
        read -r gpg_file_path
        if [ -z "$gpg_file_path" ];then
            printf "(!) Empty input (!)\n"
        elif [ -d "$gpg_file_path" ];then
            printf "(!) Input is a directory, not a gpg file (!)\n"
        elif [ -f "$gpg_file_path" ];then
            case "$gpg_file_path" in
                *.gpg )
                    src="$gpg_file_path"
                    dest="/"
                    exclude="$(printf ' --exclude=%s' $dirs_skip_list)"
                    rsync -aAX --info=progress2 $exclude "$src" "$dest"
                    ;;
                *)
                    printf "(!) Input isn't a gpg file (!)\n"
                    return
                    ;;
            esac
        else
            printf "(!) Input isn't a gpg file (!)\n"
        fi
    done
}

case "$1" in
(auto)
    backup auto
    exit 0
    ;;
(backup)
    backup
    exit 0
    ;;
(restore)
    restore
    exit 0
    ;;
(*)
    echo "Usage: $0 {backup|restore|auto}"
    exit 2
    ;;
esac

Last edited by assertion9 (2020-07-04 12:25:51)

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#3381 2020-07-08 07:17:48

YesItsMe
Member
Registered: 2017-07-12
Posts: 37

Re: Post your handy self made command line utilities

If you have a cluttered $HOME (like I do), this automatic Git updater will, at least, take care of having your local Git stuff up-to-date:

#!/opt/schily/bin/bosh
# Update all Git repositories in/below $HOME.

# ---- VARIABLES

# Contains a list of (substrings of) directories to skip.
BLACKLIST="$HOME/go/ $HOME/Library"

# Contains a list of Git repository directories.
# Currently, this is collected automatically, but it can be a
# manual list as well.
GITDIRS=`find $HOME -maxdepth 3 -name '.?*' -prune -o -type d -call '[ -e "$1/.git" ]' {} \; -prune -print`

# ---- CODE

for DIR in ${GITDIRS}; do
	# Blacklist check:
	allowed=1
	for BAN in ${BLACKLIST}; do
		substrings=`expr "$DIR" : "$BAN"`
		if [ $substrings -ne 0 ] ; then
			# This directory is in/below a blacklisted one.
			allowed=0
			break
		fi
	done

	if [ $allowed -eq 0 ]; then
		continue
	fi

	# This directory is promised to be not blacklisted.
	# Process it.
	cd $DIR

	# Check the remote state:
	git fetch

	UPSTREAM=${1:-'@{u}'}
	LOCAL=`git rev-parse @`
	REMOTE=`git rev-parse "$UPSTREAM"`
	BASE=`git merge-base @ "$UPSTREAM"`

	if [ $LOCAL = $REMOTE ]; then
		# This repository is up-to-date.
		# Do nothing with it.
		continue
	elif [ $LOCAL = $BASE ]; then
		# The remote version is newer.
		echo "Updating Git repository: $DIR"
		git pull
	else
		# Something is different.
		echo "The Git repository in $DIR needs to be merged."
		echo "This cannot be done automatically."
	fi
done

Note that you’ll need to change the GITDIRS call if you’re using a non-Schily POSIX shell.

Last edited by YesItsMe (2020-07-08 07:18:09)

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#3382 2020-07-30 09:47:58

Ferdinand
Member
Registered: 2020-01-02
Posts: 8

Re: Post your handy self made command line utilities

Here's one I use to move my camera files out of a folder and into parallel folders named from the file dates.

The workflow being something like this:

  1. Copy files from the camera into a folder "Newstuff"

  2. cd to "Newstuff" and run the script

  3. The new files are then moved to date-named folders, parallel to "Newstuff"

It has lots of improvement potential; I don't think it handles files with spaces well, and it could need a nicer confirmation dialogue to avoid calling it in the wrong folder (which can cause a real mess yikes )

#!/bin/bash

group_by_date () {
    for file in `ls`; do
        filedate=`stat -c %y $file | cut -d ' ' -f 1`
        if [ -d ../$filedate ]; then
            mv $file ../$filedate
        else
            mkdir ../$filedate
            mv $file ../$filedate
        fi
    done
}

# Make sure I do this from the correct directory
echo "Do you want to group by date the files in $PWD?"
select yn in "Yes" "No"; do
    case $yn in
        Yes ) group_by_date; break;;
        No ) exit;;
    esac
done

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#3383 2020-07-30 12:46:59

teckk
Member
Registered: 2013-02-21
Posts: 386

Re: Post your handy self made command line utilities

Another way without parsing ls, or using cut.

for file in *; do
    filedate=$(date +%F -r "$file")
    echo "$filedate"
done

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#3384 2020-07-30 13:41:00

Trilby
Inspector Parrot
Registered: 2011-11-29
Posts: 24,404
Website

Re: Post your handy self made command line utilities

This will do everything in the group_by_date function:

stat -c "%y %n" * | while read date time offset file; do
   mkdir -p ../$date
   mv "$file" ../$date
done

No need to parse ls, and only one subshell and one stat process total, rather than one subshell per file and a stat process per file.

EDIT: changed $date to ../$date as this is intended to be a relative directory.

Last edited by Trilby (2020-07-30 13:45:57)


"UNIX is simple and coherent..." - Dennis Ritchie, "GNU's Not UNIX" -  Richard Stallman

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#3385 2020-08-10 05:35:13

monodromy
Member
Registered: 2014-02-08
Posts: 60

Re: Post your handy self made command line utilities

exiftool can also do this; for example:

exiftool '-Directory<DateTimeOriginal' -d %Y/%m/%d dir

Offline

#3386 2020-08-19 13:19:48

poire
Member
Registered: 2019-09-02
Posts: 2

Re: Post your handy self made command line utilities

Here is a script I use that notifies whats playing through pulseaudio. Works nicely with mpv.

#!/bin/bash
#
# Init variables
#
notification_title="Now Playing"
while [ true ]
do
        #
        # Get the current media.name playing according to pactl
        #
        name=$(pactl list | grep "media\.name.* - " | awk -F "=" '{print substr($2,3,length($2)-3)}')
        #
        # Only display the name if it differs from the previous one
        #
        if [ -n "$name" ] && [ "$name" != "$plays" ]; then
          plays="$name"
                #
                # If X is running, notify, else echo to the terminal
                #
                if [[ $DISPLAY ]]; then
                        notify-send "$notification_title" "$plays" > /dev/null 2>&1
                else
                        echo "$plays"
                fi
        fi
        #
        # Check every 5 seconds for a changed title playing
        #
        sleep 5
done

Offline

#3387 2020-08-19 14:24:13

Trilby
Inspector Parrot
Registered: 2011-11-29
Posts: 24,404
Website

Re: Post your handy self made command line utilities

Poire, why do you use [ and [[ interchangeably?  You have bash as the shebang, so there shouldn't be any need for [.  Most notably, it's a complete no-op (but resource use) each time through the while loop.  Don't test for an infinite loop:

while true
  ...

There's also no point in piping grep to awk:

name=$(pactl list | awk -F =  '/media\.name.* -/ {print ...

You could also skip checking if name is non-empty every time through the loop, simply by setting 'plays' to some arbitrary string before the loop.


"UNIX is simple and coherent..." - Dennis Ritchie, "GNU's Not UNIX" -  Richard Stallman

Offline

#3388 2020-08-19 16:00:19

Awebb
Member
Registered: 2010-05-06
Posts: 5,586

Re: Post your handy self made command line utilities

Trilby wrote:

Poire, why do you use [ and [[ interchangeably?  You have bash as the shebang, so there shouldn't be any need for [.  Most notably, it's a complete no-op (but resource use) each time through the while loop.  Don't test for an infinite loop:

while true
  ...

There's also no point in piping grep to awk:

name=$(pactl list | awk -F =  '/media\.name.* -/ {print ...

You could also skip checking if name is non-empty every time through the loop, simply by setting 'plays' to some arbitrary string before the loop.

I thought the point of piping grep into awk was not actually knowing any awk and giving up on googling "how to X with sed and grep" and using that one line from sack overflow

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#3389 2020-08-19 16:51:20

Trilby
Inspector Parrot
Registered: 2011-11-29
Posts: 24,404
Website

Re: Post your handy self made command line utilities

Yeah, pretty much.  But in this case, it's trivial - line matching is a fundamental aspect of awk like search and replace is a fundamental aspect of sed.  I may get irked when that's all people know how to do with it, but most people know at least how to do that.

Last edited by Trilby (2020-08-19 18:57:39)


"UNIX is simple and coherent..." - Dennis Ritchie, "GNU's Not UNIX" -  Richard Stallman

Offline

#3390 2020-08-19 18:56:45

seth
Member
Registered: 2012-09-03
Posts: 16,546

Re: Post your handy self made command line utilities

Awebb wrote:

how to X with sed and grep

Without grep …

Also: https://www.google.com/search?q=greatest+awk+tutorial smile

Offline

#3391 2020-08-26 13:11:34

Awebb
Member
Registered: 2010-05-06
Posts: 5,586

Re: Post your handy self made command line utilities

Inspired by this thread, I thought I'd play around a bit with the AURWeb RPC, curl and jq.

It needs jq, curl and expac.

#/usr/bin/bash
url='https://aur.archlinux.org/rpc.php'
preamble='/rpc/?v=5&type=info'
packages=$(pacman -Qqm)
searchstring=$(echo '&arg[]='$packages | sed 's/\ /\&arg[]=/g')
searchresult=$(curl -s $url$preamble$searchstring)

for pkg in $packages
do
        remoteversion=$(echo $searchresult | jq --arg PKG "$pkg" '.results[] | select(.Name == $PKG) | .Version' | sed 's/"//g')
        localversion=$(expac %v $pkg)
        if [[ $remoteversion > $localversion ]]
        then
                echo "$pkg needs an update $localversion -> $remoteversion"
        elif [[ $localversion > $remoteversion ]]
        then

                if [[ $pkg =~ "-git" ]]
                then
                        echo "$pkg AUR is behind local: $localversion > $remoteversion"
                else
                        echo "$pkg AUR is behind local or version string format mismatch! $localversion > $remoteversion"
                fi
        else
                if [[ $pkg =~ "-git" ]]
                then
                        echo "$pkg is up-to-date according to the AUR. Check upstream."
                else
                        echo "$pkg is up-to-date."
                fi
        fi
done

I tried to include some error handling and there is no flood control for the response limit yet. This is mostly a POC, that anybody with an hour to spare can write their own AUR helper.

Last edited by Awebb (2020-08-26 13:12:33)

Offline

#3392 2020-08-26 13:17:31

Trilby
Inspector Parrot
Registered: 2011-11-29
Posts: 24,404
Website

Re: Post your handy self made command line utilities

FYI:

searchstring=$(printf '&arg[]=%s' $packages)

Also, I don't think shell test comparisons will be very robust in version checks.

That is about how my tool writen in python works though - where it can use LooseVersion from distutils.version for the checks.

Last edited by Trilby (2020-08-26 13:19:41)


"UNIX is simple and coherent..." - Dennis Ritchie, "GNU's Not UNIX" -  Richard Stallman

Offline

#3393 2020-08-26 14:22:41

Awebb
Member
Registered: 2010-05-06
Posts: 5,586

Re: Post your handy self made command line utilities

Trilby wrote:

FYI:

searchstring=$(printf '&arg[]=%s' $packages)

That is cool! I need to up my printf game.

Trilby wrote:

Also, I don't think shell test comparisons will be very robust in version checks.

Yes, I was betting on this from "help test"

      STRING1 > STRING2
                     True if STRING1 sorts after STRING2 lexicographically.

I'm aware that this is a hard gamble, because [[ ]] isn't "test". I think I'll burn that particular bridge when I cross it. I probably should write this in Python, but bash is my pocket knife on Linux, so I try to do as much in bash as possible, even if it ends up eating the cat.

Offline

#3394 2020-09-20 11:06:40

Head_on_a_Stick
Member
From: London
Registered: 2014-02-20
Posts: 5,542
Website

Re: Post your handy self made command line utilities

Script to change the backlight level:

#!/bin/sh

echo()
{
   printf %s\\n "$*"
}

usage()
{
   echo "Use '${0##*/} up' & '${0##*/} down' to set the backlight level"
}

get_increment()
{
   IFS= read -r max < "${file%/*}"/max_brightness
   increment=$((max/10))
}

get_brightness()
{
   IFS= read -r brightness < "$file"
}

brighter()
{
   for file in /sys/class/backlight/*/brightness; do
      get_increment
      get_brightness
      echo $((brightness+increment)) > "$file"
   done
}

dimmer()
{
   for file in /sys/class/backlight/*/brightness; do
      get_increment
      get_brightness
      echo $((brightness-increment)) > "$file"
   done
}

main()
{
   case "$1" in
      up) brighter ;;
      down) dimmer ;;
      *) usage ;;
   esac
}

main "$1"

Add a line to /etc/sudoers to allow any user to run it from a keybind with sudo (add 'up' & 'down' as arguments to the script):

ALL = (root) NOPASSWD: /full/path/to/script

Any corrections, suggestions or insults are gratefully welcomed smile

Offline

#3395 2020-09-20 12:15:46

kokoko3k
Member
Registered: 2008-11-14
Posts: 2,034

Re: Post your handy self made command line utilities

hi, can you explain me this assignment syntax?

IFS= read -r brightness < "$file"

Offline

#3396 2020-09-20 12:47:08

Head_on_a_Stick
Member
From: London
Registered: 2014-02-20
Posts: 5,542
Website

Re: Post your handy self made command line utilities

^ It assigns the numerical value in "$file" to the "$brightness" variable.

Offline

#3397 2020-09-20 12:58:40

Trilby
Inspector Parrot
Registered: 2011-11-29
Posts: 24,404
Website

Re: Post your handy self made command line utilities

Is that meant as a joke?  You turned what should be about a dozen lines into 50 lines just do to painful abstractions and a redefintion of the shell built in "echo" ... and you include IFS settings and read's -r when you know the data read will not have separators or escape sequences?  Why?  This would have the same result:

#!/bin/sh

case "$1" in
	up) sign=1 ;;
	down) sign=-1 ;;
	*) echo "Use '$0 up' & '$0 down' to set the backlight level"; exit ;;
esac

for file in /sys/class/backlight/*; do
	read max < $file/max_brightness
	read cur < $file/brightness
	echo $((cur + sign * max / 10)) > $file/brightness
done

My own version allows for increments / decrement, specifiying a percent, or just checking the current value with not much more code (and it also checks bounds which will allow incrementing/decrementing to 100% or 0 while your code will fail to do so):

#!/bin/sh

read max < /sys/class/backlight/intel_backlight/max_brightness
read cur < /sys/class/backlight/intel_backlight/brightness
step=80

case $1 in
        +|up) let cur+=$step ;;
        -|down) let cur-=$step ;;
        [0-9]*) cur=$((max * $1 / 100)) ;;
        *) echo $cur; exit ;;
esac

[ $cur -le 0 ] && cur=0
[ $cur -ge $max ] && cur=$max
echo $cur >> /sys/class/backlight/intel_backlight/brightness

I only have one backlight device, so there is no need to loop.

Then there is no reason to require sudo.  Add your user to the video group as recommended in the wiki.

Last edited by Trilby (2020-09-20 13:03:52)


"UNIX is simple and coherent..." - Dennis Ritchie, "GNU's Not UNIX" -  Richard Stallman

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#3398 2020-09-20 13:03:09

Head_on_a_Stick
Member
From: London
Registered: 2014-02-20
Posts: 5,542
Website

Re: Post your handy self made command line utilities

Trilby wrote:

Is that meant as a joke?

Well no but I'm glad it amused you :-)

Trilby wrote:

You turned what should be about a dozen lines into 50 lines just do to painful abstractions and a redefintion of the shell built in "echo"?  Why?

Because I'm crap at scripting big_smile

Thanks for the superior alternative, it is very much appreciated.

Oh, and I use a function for echo because I don't think it should have options. It's a religious thing.

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#3399 2020-09-20 13:05:48

Trilby
Inspector Parrot
Registered: 2011-11-29
Posts: 24,404
Website

Re: Post your handy self made command line utilities

Head_on_a_Stick wrote:

Oh, and I use a function for echo because I don't think it should have options. It's a religious thing.

Then don't pass options to echo, or just use printf from the start.  There's no need for several lines to redefine echo as printf just so you can use echo when you really wanted printf.

And sorry HoaS, my tone was inappropriate.  I was really just surprised as you are an experienced archer and I thought I've seen content from you before that displays a capacity and approach to scripting that just seemed at odds with this script.

Last edited by Trilby (2020-09-20 16:57:10)


"UNIX is simple and coherent..." - Dennis Ritchie, "GNU's Not UNIX" -  Richard Stallman

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#3400 2020-09-21 05:20:32

eschwartz
Trusted User/Bug Wrangler
Registered: 2014-08-08
Posts: 3,683

Re: Post your handy self made command line utilities

I'm strongly in favor of just forgetting "echo" exists. Use printf "%s\n" "message" everywhere. Or define

msg() { printf "%s\n" "$*"; }

which is noteworthy for not calling itself "echo" and thus not having terrible baggage.

I'm not fundamentally against the use of functions, though I don't believe it helps here, but the leaky use of globals doesn't really make a compelling argument in favor of it. Functions should be standalone abstractions. Your get_*() functions should print the values and be used like this:

increment=$(get_increment)

Of course then you realize you don't gain much *and* incur the cost of a subshell, so you might as well not bother.

(makepkg includes some abstraction functions that take as an argument, the name of a global variable to write to. If you absolutely must work without subshells, this strikes me as a lot conceptually safer than baking in variable names like that.)

inb4 "I know this script and it's really short and won't ever reuse variable names".
Counter: then you don't need convenience functions either.


Managing AUR repos The Right Way -- aurpublish (now a standalone tool)

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