Linked Questions
13 questions linked to/from Is there something wrong with my script or is Bash much slower than Python?
288
votes
5
answers
79k
views
Why is using a shell loop to process text considered bad practice?
Is using a while loop to process text generally considered bad practice in POSIX shells?
As Stéphane Chazelas pointed out, some of the reasons for not using shell loop are conceptual, reliability, ...
- 158k
23
votes
3
answers
8k
views
What is the fastest way to run a script?
I was wondering what is the fastest way to run a script , I've been reading that there is a difference in speed between showing the output of the script on the terminal, redirecting it to a file or ...
- 1,068
15
votes
2
answers
8k
views
How do I shift a bash array at some index in the middle?
1 #!/bin/bash
2 # query2.sh
3
4 numbers=(53 8 12 9 784 69 8 7 1)
5 i=4
6
7 echo ${numbers[@]} # <--- this echoes "53 8 12 9 784 69 8 7 1" to stdout.
8 echo ${numbers[i]} # <--- this echoes ...
- 455
3
votes
7
answers
2k
views
Break down string into array in shell script
I am trying to convert string for example string=11111001 to array which I will be able to access by calling respective array index like
arr[0]=1, arr[1]=0
I am new to shell scripting and from what I ...
- 41
4
votes
4
answers
6k
views
Can I use comparison operators in case?
I'm building a function that will calculate the gauge of wire required given amperage, distance(in feet), and allowable voltage drop.
I can calculate the "circular mils" given those values and with ...
- 41.6k
12
votes
2
answers
4k
views
What is the overhead of using subshells?
Hopefully this question is not too generic. I am very new to shell scripting and I come from a computer architecture/non-scripting programming background. I have noticed on the scripts at my work that ...
- 459
6
votes
1
answer
21k
views
Bash script inheritance? Calling a function from another script?
I have this line:
trap 'jobs -p | xargs kill -9' SIGINT SIGTERM EXIT
it is repeated in many bash shell scripts I have.
What is the best way to share this code? Can I call a bash function perhaps?
...
- 10.9k
4
votes
1
answer
2k
views
bash: preallocate memory for array
Can memory be preallocated in bash for arrays of a defined size? I am iteratively adding strings to an array (declared by declare -a arr) in a loop (arr+=("$str")), and am wondering whether ...
- 3,808
0
votes
3
answers
2k
views
Using AWK To Extract Numbers From .CSV File
I have a .CSV file that I need to extract numbers from. Example of file:
#File of numbers
1,2,3,4,5
6,7,8,9,10
I want to use awk (or another utility) to extract the first number and second number and ...
- 101
0
votes
2
answers
2k
views
Insert variable in variable line using sed or awk [closed]
i have two variables (txt and a line number) i want to insert my txt in the x line
card=$(shuf -n1 shuffle.txt)
i=$(shuf -i1-52 -n1)
'card' is my txt : a card randomly selected in a shuffle 'deck'
...
- 13
1
vote
1
answer
800
views
For with read value
In what way does the final value of number being assigned by read var number (and we enter 5) and number=5 differ? I was making this for loop:
read var number
#number=5
factorial=1
i=1
for i in `seq ...
- 155
0
votes
1
answer
371
views
Comparing files in awk/bash
I came across a problem and have no idea how to find the OPTIMAL solution.
I have a list of files that looks like this:
file1\0file2\0...fileX\0\0file(x+1)\0
Every name of file is separated by a \0 ...
- 191
0
votes
1
answer
241
views
How do I write a word, letter by letter into my program's memory
I'm pretty new to unix and I'm wondering how I would go about writing a word, letter by letter into my program's memory. So for example if my word was "cup", I'd want an array A to have A[0] = 'c', A[...
