Array Question

[Stang02GT]

I am learning some basic programming in linux ( Fedora 5). I am just creating some simple programs and I am wondering if anyone can help me figure this out.

I have this array....

let i=1
for array3 in "$@"
do
names[i]="$array3"
let i=i+1
done
for i in "${names[@]}"
do
echo $i
done

How can i change this script to have the data read from within the program rather then from the command line?


thank you in advance for any help!

[radoulov]

Assuming recent version of bash (as you said FC5)
and a file in the following format:

entry1
entry2
entry3

You can change the code like this:

while IFS= read -r; do
	names[((++i))]="$REPLY"
done<your_file_here

for i in "${names[@]}"; do
	printf "%s\n" "$i"
done

# or just: printf "%s\n" "${names[@]}"

[Stang02GT]

Thank you very much!!


Is there anyway you could help me understand what you did a little better?

[radoulov]

Is there anyway you could help me understand what you did a little better?

First off I have to correct my own post (++i is sufficient, you don't need (())):

while IFS= read -r; do
	names[++i]="$REPLY"
done<your_file_here

IFS= and read -r

IFS= is "clearing" the internal field separator,
otherwise leading and trailing IFS characters will
be stripped: for example, a record like " word ... "
becomes "word ...". The -r option for read is necessary
to prevent some escape sequences from being expanded
- \n will not be expanded to a new line for example
(if that's not what you want,
use just while read;do ...).

names[++i]="$REPLY"

Some recent shells like bash, ksh93 and zsh
accept the syntax ++var and var++
for incrementing the value of a variable.
$REPLY is the default variable for some
statements like read and select.

HTH a bit.