Retrieving individual element from xdotool search result with Bash script - linux

Having trouble with a bash script. I can't figure out how to get the individual pids from the xdotool search function.
Code
google-chrome --app=https://google.com &
google-chrome --app=https://google.com &
google-chrome --app=https://google.com &
google-chrome --app=https://google.com &
sleep 5
pids=$(xdotool search --onlyvisible --name google)
echo $pids
width=1920
height=1080
for i in 0 1 2 3;
do
x=$((((i)/2)*$width))
y=$(((i%2)*$height))
echo $x
echo $y
echo "${pids[$i]}"
#xdotool windowmove ${pids[i]} $x $y
done
Output
46137345 46137352 46137355 46137358
0
0
46137345
46137352
46137355
46137358
0
1080
1920
0
1920
1080
I can't see a /n in the string which is what I thought was doing it so don't know why it's making the new lines.
I'm very new to bash scripting so I have no doubt it's something stupid obvious.
I'm using bash version 5.0.3

The problem is that your pids variable is just a string but you're trying to treat it like an array.
Use an outer set of parens to make pids an array as in:
pids=($(xdotool search --onlyvisible --name google))
$ for i in "${pids[#]}"; do echo $i; done
46137345
46137352
46137355
46137358

Related

Is it possible to change the color of systemd (?) [FAILURE] [OK] or [SUCCESS] etc. in boot sequence?

My problem is, that any script / command in /etc/init.d seems to be overridden by something else or disregarded.
So I guess that this must be something to be configured in the kernel.
For example using /etc/init.d/some_script (This content is about what I want):
# Column number to place the status message
RES_COL=60
# Command to move out to the configured column number
MOVE_TO_COL="echo -en \\033[${RES_COL}G"
# Command to set the color to SUCCESS (Green)
SETCOLOR_SUCCESS="echo -en \\033[1;36m"
# Command to set the color to FAILED (Red)
SETCOLOR_FAILURE="echo -en \\033[1;31m"
# Command to set the color back to normal
SETCOLOR_NORMAL="echo -en \\033[0;39m"
# Function to print the SUCCESS status
echo_success() {
$MOVE_TO_COL
echo -n "["
$SETCOLOR_SUCCESS
echo -n $" OK "
$SETCOLOR_NORMAL
echo -n "]"
echo -ne "\r"
return 0
}
# Function to print the FAILED status message
echo_failure() {
$MOVE_TO_COL
echo -n "["
$SETCOLOR_FAILURE
echo -n $"FAILED"
$SETCOLOR_NORMAL
echo -n "]"
echo -ne "\r"
return 1
}
I've been grepping around inside the kernel- and other sources and inside the system but found nothing about that.
/drivers/tty/vt/vt.c seems to be some global config for the VT. That's not what I need.
I would be happy to receive a few tips.
Greetings
Jens
This OS uses systemd.
I just started my old computer with Mandriva 2009 and coloring worked out of the box. There is a file 'etc/sysconfig/init' in which I can set the color but here on Magaia 7.1 there is no such file. I only have /etc/init.d/functions which says:
"This file contains functions to be used by most or all shell scripts in the /etc/init.d directory."
There is a block in it showing the color configuration:
# Read in our configuration
if [ -z "${BOOTUP:-}" ]; then
if [ -f /etc/sysconfig/init ]; then
. /etc/sysconfig/init
else
# verbose ->> very (very!) old bootup look (prior to RHL-6.0?)
# color ->> default bootup look
# other ->> default bootup look without ANSI colors or positioning
BOOTUP=color
# Column to start "[ OK ]" label in:
RES_COL=60
# terminal sequence to move to that column:
MOVE_TO_COL="echo -en \\033[${RES_COL}G"
# Terminal sequence to set color to a 'success' (bright green):
SETCOLOR_SUCCESS="echo -en \\033[1;36m"
# Terminal sequence to set color to a 'failure' (bright red):
SETCOLOR_FAILURE="echo -en \\033[1;31m"
# Terminal sequence to set color to a 'warning' (bright yellow):
SETCOLOR_WARNING="echo -en \\033[1;33m"
# Terminal sequence to reset to the default color:
SETCOLOR_NORMAL="echo -en \\033[0;39m"
# Verbosity of logging:
LOGLEVEL=1
fi
if [ "$CONSOLETYPE" = "serial" ]; then
BOOTUP=serial
MOVE_TO_COL=
SETCOLOR_SUCCESS=
SETCOLOR_FAILURE=
SETCOLOR_WARNING=
SETCOLOR_NORMAL=
fi
But any changes do have no effect.
I tagged it linux-kernel because my guess was that this could be overriden by some kernel option or patch or config or someting like that.

Write output of subprocess launched by a `screen` CLI Command to a log file?

I am launching a bunch of the same script (generate_records.php) into screens. I am doing this to easily parallelize the processes. I would like to write the output of each of the PHP processes to a log file using something like &> log_$i (StdOut an StdErr).
My shell scripting is weak sauce, and I can't get the syntax correct. I keep getting the output of the screen, which is empty.
Exmaple: launch_processes_in_screens.sh
max_record_id=300000000
# number of parallel processors to run
total_processors=10
# max staging companies per processor
(( num_records_per_processor = $max_record_id / $total_processors))
i=0
while [ $i -lt $total_processors ]
do
(( starting_id = $i * $num_records_per_processor + 1 ))
(( ending_id = $starting_id + $num_records_per_processor - 1 ))
printf "\n - Starting processor #%s starting at ID:%s and ending at ID: %s" "$i" "$starting_id" "$ending_id"
screen -d -m -S "process_$i" php generate_records.php "$starting_id" "$num_records_per_processor" "FALSE"
((i++))
done
If the only reason you're using screen is to launch many processes in parallel, you can avoid it entirely and use & to start them in the background:
php generate_records.php "$starting_id" "$num_records_per_processor" FALSE &
You may also be able to remove some code by using parallel.

Bash: Split stdout from multiple concurrent commands into columns

I am running multiple commands in a bash script using single ampersands like so:
commandA & commandB & commandC
They each have their own stdout output but they are all mixed together and flood the console in an incoherent mess.
I'm wondering if there is an easy way to pipe their outputs into their own columns... using the column command or something similar. ie. something like:
commandA | column -1 & commandB | column -2 & commandC | column -3
New to this kind of thing, but from initial digging it seems something like pr might be the ticket? or the column command...?
Regrettably answering my own question.
None of the supplied solutions were exactly what I was looking for. So I developed my own command line utility: multiview. Maybe others will benefit?
It works by piping processes' stdout/stderr to a command interface and then by launching a "viewer" to see their outputs in columns:
fooProcess | multiview -s & \
barProcess | multiview -s & \
bazProcess | multiview -s & \
multiview
This will display a neatly organized column view of their outputs. You can name each process as well by adding a string after the -s flag:
fooProcess | multiview -s "foo" & \
barProcess | multiview -s "bar" & \
bazProcess | multiview -s "baz" & \
multiview
There are a few other options, but thats the gist of it.
Hope this helps!
pr is a solution, but not a perfect one. Consider this, which uses process substitution (<(command) syntax):
pr -m -t <(while true; do echo 12; sleep 1; done) \
<(while true; do echo 34; sleep 2; done)
This produces a marching column of the following:
12 34
12 34
12 34
12 34
Though this trivially provides the output you want, the columns do not advance individually—they advance together when all files have provided the same output. This is tricky, because in theory the first column should produce twice as much output as the second one.
You may want to investigate invoking tmux or screen in a tiled mode to allow the columns to scroll separately. A terminal multiplexer will provide the necessary machinery to buffer output and scroll it independently, which is important when showing output side-by-side without allowing excessive output from commandB to scroll commandA and commandC off-screen. Remember that scrolling each column separately will require a lot of screen redrawing, and the only way to avoid screen redraws is to have all three columns produce output simultaneously.
As a last-ditch solution, consider piping each output to a command that indents each column by a different number of characters:
this is something that commandA outputs and is
and here is something that commandB outputs
interleaved with the other output, but visually
you might have an easier time distinguishing one
here is something that commandC outputs
which is also interleaved with the others
from the other
Script print out three vertical rows and a timer each row containing the output from a single script.
Comment on anything you dont understand and ill add answers to my answer as needed
Hope this helps :)
#!/bin/bash
#Script by jidder
count=0
Elapsed=0
control_c()
{
tput rmcup
rm tail.tmp
rm tail2.tmp
rm tail3.tmp
stty sane
}
Draw()
{
tput clear
echo "SCRIPT 1 Elapsed time =$Elapsed seconds"
echo "------------------------------------------------------------------------------------------------------------------------------------------------------"
tail -n10 tail.tmp
tput cup 25 0
echo "Script 2 "
echo "------------------------------------------------------------------------------------------------------------------------------------------------------"
tail -n10 tail2.tmp
tput cup 50 0
echo "Script 3 "
echo "------------------------------------------------------------------------------------------------------------------------------------------------------"
tail -n10 tail3.tmp
}
Timer()
{
if [[ $count -eq 10 ]]; then
Draw
((Elapsed = Elapsed + 1))
count=0
fi
}
main()
{
stty -icanon time 0 min 0
tput smcup
Draw
count=0
keypress=''
MYSCRIPT1.sh > tail.tmp &
MYSCRIPT2.sh > tail2.tmp &
MYSCRIPT3.sh > tail3.tmp &
while [ "$keypress" != "q" ]; do
sleep 0.1
read keypress
(( count = count + 2 ))
Timer
done
stty sane
tput rmcup
rm tail.tmp
rm tail2.tmp
rm tail3.tmp
echo "Thanks for using this script."
exit 0
}
main
trap control_c SIGINT

Bash prompt with the last exit code

I've been trying to customize my Bash prompt so that it will look like
[feralin#localhost ~]$ _
with colors. I managed to get constant colors (the same colors every time I see the prompt), but I want the username ('feralin') to appear red, instead of green, if the last command had a nonzero exit status. I came up with:
\e[1;33m[$(if [[ $? == 0 ]]; then echo "\e[0;31m"; else echo "\e[0;32m"; fi)\u\e[m#\e[1;34m\h \e[0;35m\W\e[1;33m]$ \e[m
However, from my observations, the $(if ...; fi) seems to be evaluated once, when the .bashrc is run, and the result is substituted forever after. This makes the name always green, even if the last exit code is nonzero (as in, echo $?). Is this what is happening? Or is it simply something else wrong with my prompt? Long question short, how do I get my prompt to use the last exit code?
As you are starting to border on a complex PS1, you might consider using PROMPT_COMMAND. With this, you set it to a function, and it will be run after each command to generate the prompt.
You could try the following in your ~/.bashrc file:
PROMPT_COMMAND=__prompt_command # Function to generate PS1 after CMDs
__prompt_command() {
local EXIT="$?" # This needs to be first
PS1=""
local RCol='\[\e[0m\]'
local Red='\[\e[0;31m\]'
local Gre='\[\e[0;32m\]'
local BYel='\[\e[1;33m\]'
local BBlu='\[\e[1;34m\]'
local Pur='\[\e[0;35m\]'
if [ $EXIT != 0 ]; then
PS1+="${Red}\u${RCol}" # Add red if exit code non 0
else
PS1+="${Gre}\u${RCol}"
fi
PS1+="${RCol}#${BBlu}\h ${Pur}\W${BYel}$ ${RCol}"
}
This should do what it sounds like you want. Take a look a my bashrc's sub file if you want to see all the things I do with my __prompt_command function.
If you don't want to use the prompt command there are two things you need to take into account:
getting the value of $? before anything else. Otherwise it'll be overridden.
escaping all the $'s in the PS1 (so it's not evaluated when you assign it)
Working example using a variable
PS1="\$(VALU="\$?" ; echo \$VALU ; date ; if [ \$VALU == 0 ]; then echo zero; else echo nonzero; fi) "
Working example without a variable
Here the if needs to be the first thing, before any command that would override the $?.
PS1="\$(if [ \$? == 0 ]; then echo zero; else echo nonzero; fi) "
Notice how the \$() is escaped so it's not executed right away, but each time PS1 is used. Also all the uses of \$?.
Compact solution:
PS1='... $(code=${?##0};echo ${code:+[error: ${code}]})'
This approach does not require PROMPT_COMMAND (apparently this can be slower sometimes) and prints [error: <code>] if the exit code is non-zero, and nothing if it's zero:
... > false
... [error: 1]> true
... >
Change the [error: ${code}] part depending on your liking, with ${code} being the non-zero code to print.
Note the use of ' to ensure the inline $() shell gets executed when PS1 is evaluated later, not when the shell is started.
As bonus, you can make it colorful in red by adding \e[01;31m in front and \e[00m after to reset:
PS1='... \e[01;31m$(code=${?##0};echo ${code:+[error: ${code}]})\e[00m'
--
How it works:
it uses bash parameter substitution
first, the ${?##0} will read the exit code $? of the previous command
the ## will remove any 0 pattern from the beginning, effectively making a 0 result an empty var (thanks #blaskovicz for the trick)
we assign this to a temporary code variable as we need to do another substitution, and they can't be nested
the ${code:+REPLACEMENT} will print the REPLACEMENT part only if the variable code is set (non-empty)
this way we can add some text and brackets around it, and reference the variable again inline: [error: ${code}]
I wanted to keep default Debian colors, print the exact code, and only print it on failure:
# Show exit status on failure.
PROMPT_COMMAND=__prompt_command
__prompt_command() {
local curr_exit="$?"
local BRed='\[\e[0;91m\]'
local RCol='\[\e[0m\]'
PS1='${debian_chroot:+($debian_chroot)}\[\033[01;32m\]\u#\h\[\033[00m\]:\[\033[01;34m\]\w\[\033[00m\]\$ '
if [ "$curr_exit" != 0 ]; then
PS1="[${BRed}$curr_exit${RCol}]$PS1"
fi
}
The following provides a leading green check mark when the exit code is zero and a red cross in all other cases. The remainder is a standard colorized prompt. The printf statements can be modified to present the two states that were originally requested.
PS1='$(if [ $? -eq 0 ]; then printf "\033[01;32m""\xE2\x9C\x93"; else printf "\033[01;31m""\xE2\x9C\x95"; fi) \[\e[00;32m\]\u#\h\[\e[00;30m\]:\[\e[01;33m\]\w\[\e[01;37m\]\$ '
Why didn't I think about that myself? I found this very interesting and added this feature to my 'info-bar' project. Eyes will turn red if the last command failed.
#!/bin/bash
eyes=(O o ∘ ◦ ⍤ ⍥) en=${#eyes[#]} mouth='_'
face () { # gen random face
[[ $error -gt 0 ]] && ecolor=$RED || ecolor=$YLW
if [[ $1 ]]; then printf "${eyes[$[RANDOM%en]]}$mouth${eyes[$[RANDOM%en]]}"
else printf "$ecolor${eyes[$[RANDOM%en]]}$YLW$mouth$ecolor${eyes[$[RANDOM%en]]}$DEF"
fi
}
info () { error=$?
[[ -d .git ]] && { # If in git project folder add git status to info bar output
git_clr=('GIT' $(git -c color.ui=always status -sb)) # Colored output 4 info
git_tst=('GIT' $(git status -sb)) # Simple output 4 test
}
printf -v line "%${COLUMNS}s" # Set border length
date=$(printf "%(%a %d %b %T)T") # Date & time 4 test
test=" O_o $PWD ${git_tst[*]} $date o_O " # Test string
step=$[$COLUMNS-${#test}]; [[ $step -lt 0 ]] && step=0 # Count spaces
line="$GRN${line// /-}$DEF\n" # Create lines
home="$BLD$BLU$PWD$DEF" # Home dir info
date="$DIM$date$DEF" # Colored date & time
#------+-----+-------+--------+-------------+-----+-------+--------+
# Line | O_o |homedir| Spaces | Git status | Date| o_O | Line |
#------+-----+-------+--------+-------------+-----+-------+--------+
printf "$line $(face) $home %${step}s ${git_clr[*]} $date $(face) \n$line" # Final info string
}
PS1='${debian_chroot:+($debian_chroot)}\n$(info)\n$ '
case "$TERM" in xterm*|rxvt*)
PS1="\[\e]0;${debian_chroot:+($debian_chroot)} $(face 1) \w\a\]$PS1";;
esac
Improved demure answer:
I think this is important because the exit status is not always 0 or 1.
if [ $EXIT != 0 ]; then
PS1+="${Red}${EXIT}:\u${RCol}" # Add red if exit code != 0
else
PS1+="${Gre}${EXIT}:\u${RCol}" # Also displays exit status
fi
To preserve the original prompt format (not just colors),
you could append following to the end of file ~/.bashrc:
PS1_ORIG=$PS1 # original primary prompt value
PROMPT_COMMAND=__update_prompt # Function to be re-evaluated after each command is executed
__update_prompt() {
local PREVIOUS_EXIT_CODE="$?"
if [ $PREVIOUS_EXIT_CODE != 0 ]; then
local RedCol='\[\e[0;31m\]'
local ResetCol='\[\e[0m\]'
local replacement="${RedCol}\u${ResetCol}"
# Replace username color
PS1=${PS1_ORIG//]\\u/]$replacement}
## Alternative: keep same colors, append exit code
#PS1="$PS1_ORIG[${RedCol}error=$PREVIOUS_EXIT_CODE${ResetCol}]$ "
else
PS1=$PS1_ORIG
fi
}
See also the comment about the alternative approach that preserves username color and just appends an error code in red to the end of the original prompt format.
You can achieve a similar result to include a colored (non-zero) exit code in a prompt, without using subshells in the prompt nor prompt_command.
You color the exit code portion of the prompt, while having it only appear when non-zero.
Core 2$ section of the prompt: \\[\\033[0;31;4m\\]\${?#0}\\[\\033[0;33m\\]\$ \\[\\033[0m\\]
Key elements:
return code, if not 0: \${?#0} (specificly "removes prefix of 0")
change color without adding to calculated prompt-width: \\[\\033[0;31m\\]
\\[ - begin block
\\033 - treat as 0-width, in readline calculations for cmdline editing
[0;31;4m - escape code, change color, red fg, underline
\\] - end block
Components:
\\[\\033[0;31;4m\\] - set color 0;31m fg red, underline
\${?#0} - display non-zero status (by removing 0 prefix)
\\[\\033[0;33m\\] - set color 0;33m fg yellow
\$ - $ or # on EUID
\\[\\033[0m\\] - reset color
The full PS1 I use (on one host):
declare -x PS1="\\[\\033[0;35m\\]\\h\\[\\033[1;37m\\] \\[\\033[0;37m\\]\\w \\[\\033[0;33m\\]\\[\\033[0;31;4m\\]\${?#0}\\[\\033[0;33m\\]\$ \\[\\033[0m\\]"
Note: this addresses a natural extension to this question, in a more enduring way then a comment.
Bash
function my_prompt {
local retval=$?
local field1='\u#\h'
local field2='\w'
local field3='$([ $SHLVL -gt 1 ] && echo \ shlvl:$SHLVL)$([ \j -gt 0 ] && echo \ jobs:\j)'"$([ ${retval} -ne 0 ] && echo \ exit:$retval)"
local field4='\$'
PS1=$'\n'"\e[0;35m${field1}\e[m \e[0;34m${field2}\e[m\e[0;31m${field3}\e[m"$'\n'"\[\e[0;36m\]${field4}\[\e[m\] "
}
PROMPT_COMMAND="my_prompt; ${PROMPT_COMMAND}"
Zsh
PROMPT=$'\n''%F{magenta}%n#%m%f %F{blue}%~%f%F{red}%(2L. shlvl:%L.)%(1j. jobs:%j.)%(?.. exit:%?)%f'$'\n''%F{cyan}%(!.#.$)%f '
Images of prompt

Show job count in bash prompt only if nonzero

A typical prompt in bash in something like:
PS1="\u#\h:\w\$ "
The you can show the number of background jobs using \j, e.g.:
PS1="\u#\h:\w [\j]\$ "
Which is useful, because every now and then I forget I have a stopped job and only notice when it complains if I manually logout from the shell.
However, 95% of the time, the background job count is 0 and showing it in the prompt is superfluous.
How can I show the job count in the prompt, but only if it's nonzero?
You can e.g. do something like this:
PS1='\u#\h:\w $([ \j -gt 0 ] && echo [\j])\$ '
The accepted answer does not work for me (I have got Bash v4.2.46). It throws an error like this:
[: \j: integer expression expected
I had to use PROMPT_COMMAND to achieve the same functionality:
export PROMPT_COMMAND=__prompt_command
function __prompt_command() {
local JOBS=$(jobs | wc -l | tr -d 0)
PS1="\u#\h:\w [${JOBS}]\$ "
}

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