Questions tagged [function]
Questions on function usage in the context of Unix & Linux (mostly but not exclusively shell scripts). Questions on programming in Python, Perl, Ruby, etc. should be asked on Stack Overflow.
567
questions
1
vote
3
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76
views
Run nested local bash functions via ssh
I have a script like this that declares many functions which use another functions, etc.:
#!/bin/bash
function a {
...
}
function b {
...
a
...
}
...
And another script that uses ...
- 133
0
votes
1
answer
66
views
how to write function with nested commands [duplicate]
I'm trying to write a find and cd function like so:
findcd () {
cd "$(dirname "$(find '$1' -type '$2' -name '$3')")"
}
to be called like so:
find . f [FILE_NAME]
But it's ...
- 235
1
vote
1
answer
107
views
Run `git commit -m` with single quotes in zsh
I sometimes use characters such as ! and $ in commit messages, they need to be manually escaped, but not if you use single quotes like this git commit -m 'My $message here!'. I tried to write a ...
- 13
1
vote
2
answers
62
views
String Length Always Returns 2 in ZSH Function
I'm trying to bowdlerize email addresses in a fixed length text file by generating a random string the same length as the input. I'm passing the string as a backreference in sed.
To simplify, this ...
- 11
0
votes
3
answers
88
views
Does `return 0` equal `true` (in sourced script to shell's environment)?
I am working on a highly portable script that users shall source to their shells, forcing me to use POSIX scripting.
There are many useful functions in the script, one of them is special though, as ...
- 28.3k
0
votes
1
answer
59
views
How to store command with option on variable of a function in zsh?
I'm trying to learn bash scripting using freeCodeCamp tutorial for beginners on YouTube.
I'm stuck at the point where he shows how to create a function.
He saved on a variable a command with an option
...
0
votes
1
answer
52
views
Running a function as process with a set process name or id
I have a bash script set up to monitor a number of UDP streams and convert it into actionable data. My problem is that I need to set the script to periodically check to see if the stream capture is ...
- 3
2
votes
4
answers
277
views
Function's comment is not printed out when putting it before the function's header
A good and well-established guideline for commenting a shell function is to put it before the function's header. I am trying to follow these guidelines as much as I can, but this convention makes it ...
- 237
0
votes
2
answers
109
views
How we can recursively expand inline functions and aliases inside function?
Nesting problem with duck typing:
function f1 { echo $1; } #with argument
function f2 { N=$((0+1)); f$N "fff"; } #with dynamic name
Desired result:
function f2 { { echo $1; } "fff"...
- 119
0
votes
1
answer
88
views
BASH: use . instead of a space for command completion
I have bash function directory located at /git/function
This is structure:
/git/function/
├── delete
│ ├── delete.dir
│ └── delete.file
├── main.sh
├── get
│├── get.dir.sh
│└── get.file.sh
How to use ...
- 183
0
votes
0
answers
31
views
printf and echo -n Work Differently - Why? [duplicate]
echo -n
my_function() {
echo -n "$@"
}
my_function hello world
I get my desired output:
hello world
printf
my_function() {
printf "$@"
}
my_function hello world
I get only ...
- 661
0
votes
2
answers
56
views
> symbol appearing when interactively defining function in bash
The behaviour of my shell environment changed:
Earlier, when pasting a function definition e.g.
function exampleFunc {
echo hello
}
to the shell, it would display as formatted and register the ...
- 491
0
votes
1
answer
56
views
Bash create parameter named array within function
I'm attempting to write a function that writes arrays with a name that's passed in. Given the following bash function:
function writeToArray {
local name="$1"
echo "$name"
...
- 491
0
votes
0
answers
122
views
How to change the default actions for the function keys?
Most computers these days comes with function keys which already have some action setup for it. For eg; Fn+F1 will mute the device and triggers a XF86AudioMute.
How can I change this triggered action? ...
- 131
2
votes
1
answer
234
views
printf "%.3f" ${variable with newlines} - error with \n
Like HERE I have a file.csv with numbers in quotes:
"0.2"
"0.3339"
"0.111111"
To round the number (3 decimals) this solutions works great:
printf "%.03f\n" $(...
- 167
0
votes
2
answers
77
views
How to add corresponding strings to a file from another file that it shares a field with?
I have two files that both have the field "tumor id". Both are comma delimited. I need to add a field that is uniquely in file 2 to file 1, and I want to add the lines of the field according ...
0
votes
1
answer
66
views
Processing a multiline variable line by line within a bash function
Is it possible to process a multiline variable in a bash function? Suppose I have a function theone and I pass a multiline variable to it.
var="
This
is a
multiline
variable"
theone "...
- 1,183
0
votes
1
answer
1k
views
How to return from bash functions the right way?
This script, which i source in my terminal, offers the function _cphetzner, that is used to create a git repository. This function uses another function _feed_variable that prompts user for missing ...
- 1
0
votes
2
answers
45
views
How to pass commands around?
I have this simple script, which does nothing more than:
check if an email matches a specific pattern
in that case, add a tag to a taglist
before quitting, print that taglist
set -e
lista_tag=()
...
-1
votes
2
answers
138
views
Local variables in bash functions
I am getting confused about setting local variables in bash functions.
It seems that using
local dgt
local ltr
local braces
local da
could be safer than using
local dgt ltr braces da
I am ...
- 1,183
0
votes
1
answer
28
views
function that allows different outputs dependent on argument values
With the following function I want to be able to call it
with nico-usage or with a numeric value to print a different string.
Con this be cleaned up or made easier.
nico-usage ()
{
local ...
- 1,183
1
vote
1
answer
192
views
How to write a function that takes an argument string that does not need to be quoted?
I'm writing a function, adding it to ~/.zshrc on my Mac. It's in order to more quickly handle commands to youtube-dl.
I have this:
function dlv()
{
cd /Users/admin/Downloads
youtube-dl ...
0
votes
2
answers
49
views
Shell function to center its first argument
In the nano text editor, I can pipe the selection into a command, and I quite often need to center text, so I came up with the following code
center() {
str=$1
# Strip leading and trailing ...
user550837
3
votes
0
answers
122
views
Why do backgrounded commands in Zsh functions not show correctly in jobs?
In Bash 5.2, the output of jobs after either of the following is identical modulo job numbers:
sleep 3
# press C-z
s() { sleep 3; }
s
# press C-z
In both, jobs produces something like
[1]+ Stopped ...
- 492
1
vote
0
answers
69
views
Avoiding support bash functions to show up in terminal sessions when tab-completing
I have a number of bash functions which I source from my .bashrc. I also have a bunch of support function that are needed but do not want them to show up in a terminal session when a user does tab-...
- 1,183
0
votes
2
answers
146
views
Compare Execution Times of Two Functions
I am attempting to write a function which will take two commands as inputs, time the executions of both of them, then output those times to a text file. After reading this post, I got most of the way ...
- 115
1
vote
0
answers
74
views
startx function/alias has wrong arguments if not prefixed with exec
For context, my file/directory structure and contents are mostly copied from how it is in Luke Smith's dotfiles (voidrice). Also, the "..." lines in the code blocks aren't code and represent ...
- 11
0
votes
0
answers
10
views
Linux regex in substitution of a string passing argument from CLI [duplicate]
I have wrote the simple script
#!/bin/bash
progname=$1
sed -i.bak 's/#define SFFX "_.*"/#define SFFX "_$progname"/' path/to/file
In order to find a preprocessor directive in a C ...
- 113
1
vote
1
answer
94
views
Bash Function Grep Mod
TL:DR How do I add a grep to a bash function while allowing a variable number of optional inputs?
I find that in repeated grepping of large outputs, I end up clogging the terminal with data. ...
- 115
1
vote
2
answers
548
views
How can I/Should I default flags when running a command?
For context, I'm using zsh. Every time I use locate, I want to pass the -i and -A flags.
Usually, if I can get away with it, I create an alias with the same name as the existing command to do this. ...
- 821
5
votes
4
answers
769
views
How can I make time measurement DRY in my bash scripts?
Based on this answer, to measure the time in my bash scripts I can use:
start_time="$(date -u +%s.%N)"
sleep 5
end_time="$(date -u +%s.%N)"
elapsed="$(bc <<<"$...
- 639
1
vote
2
answers
297
views
zsh: alias or shell function to only echo its command line, including shell control characters
Using zsh, I'd like to create an alias or a shell function that operates as follows:
I want this alias or shell function to echo its command line without honoring any shell control characters such as &...
- 565
0
votes
2
answers
100
views
Using bash return depending on return status of last command executed within a function
I have the following bash function that returns 0 when tho variable verbos is defined. Have read the bash manual which says that when return command return N, the N is omitted, the return status is ...
- 1,183
0
votes
1
answer
125
views
How to create functions using for loops?
I'm trying to use a for loop to create functions for choosing passwords in my Arch install script (based on easy-arch) using the following code (which uses this se answer for repeating prompts and ...
- 21
3
votes
4
answers
521
views
Bash function inside function: How to interpolate certain variables from outer function
I'm trying to create a function that creates a function. I want to "hardcode" an argument in the inner function based on what is passed into the outer function, e.g.
outer() {
inner() { ...
- 673
5
votes
1
answer
930
views
zsh: pass variable by reference, and modify its value (like bash's local -n namerefs)?
Is it possible to pass a variable to a zsh function, and modify its value without using eval? I came across a bash way to do that: local -n: https://stackoverflow.com/a/50281697
- 576
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votes
0
answers
394
views
how to run locally defined function on ssh remote-host?
I'm using bash, and below is my sample script.
I've defined a function for remote ssh host, that runs another function. but when executed, it doesn't print anything.
#!/usr/bin/env bash
wdir=/var/www/...
- 1,899
2
votes
1
answer
228
views
BASH: is it possible to change a prompt of function based on its parameter?
I want to construct a function that will change its user input prompt based on its parameter.
my_fucntion takes 1 parameter as db_host after prompting the user for input:
function provide_host () {
...
- 1,899
2
votes
1
answer
341
views
How to preserve parameter expansion passed to a function?
I have this function:
cyan=`tput setaf 6`
reset=`tput sgr0`
function Info()
{
echo "${cyan}$1${reset}"
}
And I use it in my other scripts as simple as Info some message.
However, when I ...
- 639
1
vote
1
answer
153
views
zsh parameter substitution
This page has a demo function as follows:
~inews> namedir () { $1=$PWD ; : ~$1 }
But when I try it on my machine, it produces the following error:
namedir: no such file or directory: test=/home/...
- 11
0
votes
1
answer
351
views
GNU parallel export function output to variables failed
This script is to determine when destination file already exist, source file will update the destination one or be removed according to flag "$dup_act".
#!/bin/bash
dup_chk()
{
# $1: f_src,...
0
votes
1
answer
163
views
How to Control Number of Parameters Entered to Function
I am trying to make a simple menu-driven calculator script. I want there to be an error message displayed whenever the user does not enter the correct parameters when they call the add() or subtract() ...
2
votes
2
answers
577
views
How to put command in terminal prompt without executing
I know you can simply put what you'd like to run:
func()
{
cd scripts
./excellent/script
}
but, what I'd like to do instead is have ./excellent/script be put in
my commandline without being ...
- 687
3
votes
1
answer
177
views
Making simple backup alias / function?
OK, so all I really want to do is backup single files as a time in the current directory with '.bak' extension.
Here is my current function that does this (jsyk, using Rocky Linux):
function backup { ...
- 93
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1
answer
122
views
What would be a typical usecase to use a lambda expression in Bash?
This is not a "problem to solve" question but rather a question about Bash didactics, literature and what's common between teachers.
What would be a typical usecase to use an anonymous/...
0
votes
0
answers
357
views
Is valid use 'source' within a function?
Like an introduction: if secondary.sh has
functionX(){
...
}
and primary.sh has - source secondary.sh declared - and its own functions, therefore:
# primary.sh content
source secondary.sh
...
- 1,570
0
votes
0
answers
196
views
Passing one or more files in function in bash
Here I have written a sample bash script, the problem with this is that I am able to successfully pass file to function remFun but I am unable to pass the file unique.txt to function printfile. In ...
- 5
1
vote
1
answer
246
views
How to call many shell functions from sudo?
I have a huge alias file sourced by ~/.bashrc or ~/.zshrc which contains both simple aliases and more functions for more complex stuff:
# example aliases
alias "sudo=sudo "
alias "...
- 175
2
votes
2
answers
496
views
Bash function to count the number of nested parentheses
I would like to create a bash function that, given a string, it count the depth level of nested parentheses, and return -1 if the parentheses are not balanced:
function countNested(){
str="$1&...
- 405
0
votes
1
answer
153
views
Calling a function from terminal without export from sources file [duplicate]
Have added a number of functions which I source from my .bashrc. For instance, I use
export -f calc
I also have another function usage_calc where I comment out the export call
# export -f usage_calc
...
- 1,183