[SOLVED] Why does it work in a terminal but not in a script

Roken · 2019-09-26 19:54:07

Please move this if required.

I'm not sure if I have a problem with my RAM (there are reasons I may think this that I won't go into), or a problem with conky, but the symptom is that conky's own memory bar will suddenly report either 0% used and the bar will show full, or it will work. As debugging, I decided to replace the internal function with a bash script and see how that goes, but here's the rub. If I enter:

TOT=`free | grep Mem | awk '{print $2}'` ; USED=`free | grep Mem | awk '{print $3}'` ; MEMUSED=`echo $USED/\($TOT/100\) | bc` ; echo $MEMUSED%

into a terminal, it works just fine, outputting the used RAM as a percentage of the total.

However, this simple script:

#!/bin/bash
TOT=`free | grep Mem | awk '{print $2}'` ; USED=`free | grep Mem | awk '{print $3}'` ; MEMUSED=`echo $USED/\($TOT/100\) | bc` ; echo $MEMUSED%

outputs diddly squat.

Why?

EDIT: even a script with just the #!/bin/bash header and

TEST=`free | grep Mem` ; echo $TEST

outputs nothing

Last edited by Roken (2019-09-29 16:26:46)

ewaller · 2019-09-26 20:02:11

Just a hunch, but I bet it has to do with the back-ticks. Try replacing ` ... ` with $( ... )

Swiggles · 2019-09-26 20:04:52

Maybe locale related? Try specifying it in your script:

#!/bin/bash
LANG=C
TOT=`free | grep Mem | awk '{print $2}'` ; USED=`free | grep Mem | awk '{print $3}'` ; MEMUSED=`echo $USED/\($TOT/100\) | bc` ; echo $MEMUSED%

Or simplify:

Print all with label:

free | awk 'FNR>1{print $1 $3/($2/100)"%"}'

Print only mem without label:

LANG=C free | awk '$1~/Mem/{print $3/($2/100)"%"}'

Last edited by Swiggles (2019-09-26 20:21:26)

jasonwryan · 2019-09-26 20:39:46

Also, awk and grep are redundant: eg.,

free | awk '/Mem/ {print $2}'

Roken · 2019-09-26 21:03:09

Nope. None of the suggested solutions works in a script (but work directly in a terminal).

This has had me stumped for a week. All of my other personal scripts work. I deleted this one and started again, but it just doesn't want to output anything (and since I'm planning on using it in conky, output is kinda required)

jasonwryan · 2019-09-26 21:05:47

The script is executable, right?

set -x

Swiggles · 2019-09-26 21:11:26

Please give the output of

pacman -Qo /bin/bash
pacman -Qkk bash

Also try some other shell in your shebang.

Edit:

What is the output of "free"?

Last edited by Swiggles (2019-09-26 21:12:33)

seth · 2019-09-26 22:18:29

EDIT: even a script with just the #!/bin/bash header and
TEST=`free | grep Mem` ; echo $TEST
outputs nothing

run only "free" to see what is actually printed, but I'm w/ Swiggles initial guess and would "export LC_ALL=C", also you should drastically simplify this (as mentioned by everyone ;-)

#!/bin/sh
LC_ALL=C free | awk '/Mem/ {print 100*$3/$2"%"}'

Roken · 2019-09-27 05:20:52

OK, in order:

yes, the script is executable:

-rwxr-xr-x   1 steve   65 Sep 27 06:13 memfree

$pacman -Qo /bin/bash
/usr/bin/bash is owned by bash 5.0.011-1
$pacman -Qkk bash
backup file: bash: /etc/bash.bashrc (Modification time mismatch)
backup file: bash: /etc/bash.bashrc (Size mismatch)
warning: bash: /usr/bin (UID mismatch)
bash: 241 total files, 1 altered file
$free
              total        used        free      shared  buff/cache   available
Mem:       16395012     1503444    14112220      154200      779348    14447412
Swap:      18754556           0    18754556

I've also tried with one of the simplified options (I would have gotten around to simplifying, the original script was whilst I was working on getting where I wanted to be) with the same result.
I'm not sure about the UID mismatch but other scripts work fine

jasonwryan · 2019-09-27 05:31:32

jasonwryan wrote:

set -x

Awebb · 2019-09-27 05:57:22

jasonwryan wrote:

jasonwryan wrote:
set -x

This. Your one-liner works for me in a script.

seth · 2019-09-27 06:55:24

When

seth wrote:

run only "free" to see what is actually printed

seth meant "in the script" - we know it works in the interactive shell.
We know

TEST=`free | grep Mem` ; echo $TEST

fails, we know the simplified version w/o variable assignment fail, if "free | grep Mem" produces no output, "Mem" is not in the output of "free" or grep is broken (but the awk only versions alos failed…)

eda2z · 2019-09-27 13:54:49

If I take the original one-liner, place it in a file (broken.sh), change it to executable (chmod +x broken.sh) and execute it from the command line, I get the same results as if I execute the one-liner directly from the command line. I don't think my environment is much different from yours but if I execute 'pacman -Qkk bash' I do not get any errors. Also, my system shows a bash in both /bin and /usr/bin with the same inode number (hard link). Have you tried a shebang of '#!/usr/bin/env bash'?

Roken · 2019-09-28 09:58:14

Thanks, all. I took a different approach. Since this is to replace the conky builtin memory bar, I simply built it in to conkyrc directly, and it's working fine that way. For info:

${color5}RAM:$color8}${goto 70}${execbar free | awk '$1~/Mem/{print $3/($2/100)}'}${alignr}${color}${exec free | awk '$1~/Mem/{printf "%0.0f\n",$3/($2/100)"%"}'}%

Last edited by Roken (2019-09-28 09:58:55)

Trilby · 2019-09-28 12:19:14

I'm glad you have a solution that worked for you. But you were given several suggested diagnostic tests in this thread, some of them repeated multiple times and you ignored almost every single one of them. Do not ask for help here if you don't want help. If you only intend to track your independent progress ignoring almost all input, then do so on a blog.

Roken · 2019-09-29 06:29:00

Trilby wrote:

But you were given several suggested diagnostic tests in this thread, some of them repeated multiple times and you ignored almost every single one of them.

My apologies.

ALL of the diagnostic tests had the same result. Absolutely nothing.

Do not ask for help here if you don't want help.

Nice attitude.

seth · 2019-09-29 06:41:13

You got "Absolutely nothing" with either running "free" or "set -x" on top of the script?????
Nothing like is "Absolutely no output"???

Roken · 2019-09-29 10:12:25

Absolutely nothing. i.e. it returned to the prompt with diddly squat.

steve@Tex:(11:13)~$ cat scripts/memfree 
#!/bin/bash
set -x
free
steve@Tex:(11:13)~$ memfree 
steve@Tex:(11:13)~$

Oh, and before you ask, the path is in $PATH, and in fact, all the other scripts there work.

Last edited by Roken (2019-09-29 10:15:33)

Swiggles · 2019-09-29 11:19:00

What is

whence memfree

?

Trilby · 2019-09-29 12:35:12

And the output of `pacman -Qo bash` and `pacman -Qkk bash` returned absolutely no results? I highly doubt that. And you tried another shell in the shebang? I'm doubting that too. In any case, there's nothing more to be done here so I'll leave it be.

@swiggles, isn't `whence` a zsh-only command?

Last edited by Trilby (2019-09-29 12:35:58)

Swiggles · 2019-09-29 12:55:32

Trilby wrote:

@swiggles, isn't `whence` a zsh-only command?

ksh is the origin I think, but you might be right, I am so used to zsh myself. Good catch, sorry!

Use "type" instead for bash (is the same as "whence -v"):

type memfree

ewaller · 2019-09-29 15:44:52

my $0.02

ewaller@odin/home/ewaller % ls -l test
-rwxr-xr-x 1 ewaller ewaller 24 Sep 29 08:40 test
ewaller@odin/home/ewaller % cat test
#!/bin/bash
set -x
free
ewaller@odin/home/ewaller % test
ewaller@odin/home/ewaller[1] % which test
/usr/bin/test
ewaller@odin/home/ewaller % ./test 
+ free
              total        used        free      shared  buff/cache   available
Mem:       16328056     1836048     1050568      332740    13441440    13817324
Swap:      46283772       26112    46257660
ewaller@odin/home/ewaller %

Roken · 2019-09-29 16:12:11

@Trilby

Output of -Qo and -Qkk in post #9

Honestly, whilst I would like to know the reason for this, if people are going to criticize me for not responding to tests, please check that I haven't, first. I was brought up in an age when we learned it's nice to be nice, and to check.

Last edited by Roken (2019-09-29 16:14:23)

seth · 2019-09-29 16:14:41

Check what memfree is actually resolved to because there's no way the script is executed at all.
You may also try to invoke it by its full path.

Roken · 2019-09-29 16:26:13

Seth, you may have it. Naming it memfree seems to be the problem, and there is a library by the same name. Renaming gets it going.

I have no idea what memfree actually is, but gonna make this solved.

Arch Linux

#1 2019-09-26 19:54:07

[SOLVED] Why does it work in a terminal but not in a script

#2 2019-09-26 20:02:11

Re: [SOLVED] Why does it work in a terminal but not in a script

#3 2019-09-26 20:04:52

Re: [SOLVED] Why does it work in a terminal but not in a script

#4 2019-09-26 20:39:46

Re: [SOLVED] Why does it work in a terminal but not in a script

#5 2019-09-26 21:03:09

Re: [SOLVED] Why does it work in a terminal but not in a script

#6 2019-09-26 21:05:47

Re: [SOLVED] Why does it work in a terminal but not in a script

#7 2019-09-26 21:11:26

Re: [SOLVED] Why does it work in a terminal but not in a script

#8 2019-09-26 22:18:29

Re: [SOLVED] Why does it work in a terminal but not in a script

#9 2019-09-27 05:20:52

Re: [SOLVED] Why does it work in a terminal but not in a script

#10 2019-09-27 05:31:32

Re: [SOLVED] Why does it work in a terminal but not in a script

#11 2019-09-27 05:57:22

Re: [SOLVED] Why does it work in a terminal but not in a script

#12 2019-09-27 06:55:24

Re: [SOLVED] Why does it work in a terminal but not in a script

#13 2019-09-27 13:54:49

Re: [SOLVED] Why does it work in a terminal but not in a script

#14 2019-09-28 09:58:14

Re: [SOLVED] Why does it work in a terminal but not in a script

#15 2019-09-28 12:19:14

Re: [SOLVED] Why does it work in a terminal but not in a script

#16 2019-09-29 06:29:00

Re: [SOLVED] Why does it work in a terminal but not in a script

#17 2019-09-29 06:41:13

Re: [SOLVED] Why does it work in a terminal but not in a script

#18 2019-09-29 10:12:25

Re: [SOLVED] Why does it work in a terminal but not in a script

#19 2019-09-29 11:19:00

Re: [SOLVED] Why does it work in a terminal but not in a script

#20 2019-09-29 12:35:12

Re: [SOLVED] Why does it work in a terminal but not in a script

#21 2019-09-29 12:55:32

Re: [SOLVED] Why does it work in a terminal but not in a script

#22 2019-09-29 15:44:52

Re: [SOLVED] Why does it work in a terminal but not in a script

#23 2019-09-29 16:12:11

Re: [SOLVED] Why does it work in a terminal but not in a script

#24 2019-09-29 16:14:41

Re: [SOLVED] Why does it work in a terminal but not in a script

#25 2019-09-29 16:26:13

Re: [SOLVED] Why does it work in a terminal but not in a script

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