Questions tagged [variable]
A variable is a name, if correctly chosen with a symbolic meaning, that holds a value or values. Use this tag if your question is specific on the use of variables on shell scripting (if you want to ask about variables in programming languages you should probably ask on StackOverflow)
1,230 questions
0votes
2answers
73views
How to apply an ls to a file name with spaces in a variable
This code my_file="/tmp/file_without_spaces" if [ -f "${my_file}" ]; then my_ls_aaaammgg_hhss="$(ls ${my_file} -l --time-style='+%Y%m%d_%H%M%S' | cut -d' ' -f6)" mv &...
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-1votes
2answers
67views
set output into variable from grep from input variable
whats wrong with this bash script: acme2=$(dig txt @$1 _acme-challenge.$1.de) acme3=$(echo $acme2 | grep "^_acme") ...
-3votes
1answer
77views
Need working examples of using tilde expansion immediately following the : (colon) sign in variable assignment
In the Bash manual, it is written about the tilde expansion: Each variable assignment is checked for unquoted tilde-prefixes immediately following a ‘:’ or the first ‘=’. Read the Bash manual about ...
1vote
3answers
84views
Bash/macOS: Getting a variable by its name, inside of a function [duplicate]
In Bash for macOS, I need to be able to pass a string to a function and return the value of a variable named after that string, as well as the string itself. Here's what I have so far, which doesn't ...
- 111
1vote
1answer
53views
Zsh’s autocompletion options from variable
General overview I have to set a values auto-completion in zsh for a command (in the following minimal example, I will show it with testcmd). So my current code work quiet well with hardcoded values: ...
- 1,412
1vote
1answer
46views
How To Use Quotes In Variable In Bash [duplicate]
I need to assign a command to a variable and execute it with variable in linux bash. The command executes fine from command line but not from the variable because of multiple quotes. I hope backslash ...
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5votes
4answers
520views
Getting multiple variables from the output of docker exec command in a bash script?
I would like to execute a script on a host machine (script_on_host.sh), which then reaches inside a docker container in order to grab some data using a second script (script_in_container.sh). The data ...
- 293
3votes
1answer
145views
Write the contents of a .conf file into a variable located in a separate .conf file
I am configuring my hyprland.conf file and I am attempting to do it in a clean and modular fashion. I am trying for a modular fashion so that I can share my dotfiles and someone else can change which ...
-1votes
1answer
78views
Bash local nameref declaration does not work
I am trying to set a local variable in a function with nameref. The script code is the following: #!/usr/bin/bash msg=hello myparam='' superfunc () { productfile=$1 local -n refmyparam=$2 } ...
- 460
1vote
1answer
72views
How can you echo a variable name made of variable names I.e $$var1$var2 [duplicate]
In this test I'm expecting it to print "var1 is 999". user@penguin:~$ for num in {1..3}; do export var$num=9999 ; echo var$num is $var$num ; done var1 is 1 var2 is 2 var3 is 3 user@penguin:~...
2votes
2answers
274views
Zsh Expanding Variables into Arrays or Lists
I looked through some of the posted threads and none of them cover my query. I have a simple line of code below which prints all the ASCII characters: echo {' '..'~'} I want to be able to use a ...
0votes
3answers
219views
Convert json data to comma separated string
I have a json object that has an unknown number of variables, like this: { "var1": 123, "var2": 456, "var3": 789 } How can I automatically convert it to form ...
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5votes
1answer
232views
How to make MAKEFLAGS=--warn-undefined-variables apply to current Makefile?
Yes I read Communicating Options to a Sub-'make' but I want to set an option for this make, not a sub-make, and set it within the Makefile, not via the command line. $ cat Makefile MAKEFLAGS = --warn-...
- 478
0votes
1answer
40views
Does Bash have an option to diagnose "expanded to empty value" variables? [duplicate]
Does Bash have an option to diagnose (and optionally abort execution) "expanded to empty value" variables? Example (hypothetical): $ bash -c 'echo $x' --xxx bash: line 1: variable 'x' ...
- 593
2votes
1answer
450views
What's the difference between '$var' and 'var' in an arithmetic expansion?
Bash accepts both these syntax: FOO=$(($BAR + 42)) and FOO=$((BAR + 42)) Which one is correct / most portable / less prone to errors? Or are both equally valid?
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