Wanting to center text

billlove · 07-25-2020, 11:13 AM

This code will justify the text "Start Program" in the left center of the terminal window. I'd like it in the center. If anyone has any suggestions, much appreciated.

cols=$( tput cols )
rows=$( tput lines )

message=Start Program

input_length=${#message}

half_input_length=$(( $input_length / 2 ))

middle_row=$(( $rows / 2 ))
middle_col=$(( ($col /2 ) - half_input_length ))

tput clear

tput cup $middle_row $middle_col
tput bold

echo Start Program

tput sgr0
tput cup $( tput lines ) 0

rnturn · 07-25-2020, 11:38 AM

Quote:

Originally Posted by billlove

This code will left justify the text "Start Program" on the left side of the terminal window. I'd like it centered. If anyone has any suggestions, much appreciated.

cols=$( tput cols )
rows=$( tput lines )

message=Start Program

input_length=${#message}

half_input_length=$(( $input_length / 2 ))

middle_row=$(( $rows / 2 ))
middle_col=$(( ($col /2 ) - half_input_length ))

tput clear

tput cup $middle_row $middle_col
tput bold

echo Start Program

tput sgr0
tput cup $( tput lines ) 0

First thing, check for typos: (cols != col) and it's best to enclose strings in double quotes.

Second, You defined "$message" but didn't use it when displaying the message.

Third, I've always found it better to keep cursor positioning and the text to be displayed in the same print/echo statement. Personal preference, though:

Code:

echo "$( tput cup $middle_row $middle_col )$( tpu bold )$message"

HTH...

dmchess · 07-25-2020, 12:51 PM

I think there is a standard unix program that will center text. I'm not home right now, but I have seen something like that in Unix Power Tools.

billlove · 07-26-2020, 06:12 AM

No help what so ever - not what I expected but not surprised - so long LinuxQuestions.org

ondoho · 07-26-2020, 06:25 AM

Quote:

Originally Posted by billlove

No help what so ever - not what I expected but not surprised - so long LinuxQuestions.org

You weren't able to wait even 24h?
Well, then LQ is indeed the wrong place for you.

(My guess is OP doubleposted and received a handout elsewhere)

shruggy · 07-26-2020, 09:49 AM

@OP. With changes suggested by rnturn applied, your code works as intended:

Code:

#!/bin/sh
: ${LINES:=$(tput lines)} ${COLUMNS:=$(tput cols)}
msg='Start Program'
row=$((LINES/2)) col=$(( (COLUMNS-${#msg})/2 ))
tput -S <<!
clear
cup $row $col
bold
!
  echo "$msg"
tput sgr0
tput cup $LINES 0

@dmchess. No, the example in Unix Power Tools shows how to center each line in a file. It uses printf for this. Well, it is actually an awk script there that boils down to

Code:

awk -v c=$COLUMNS '{printf"%"int((c+length())/2)"s\n",$0}'

[() after length could be omitted in some versions of awk (gawk, mawk, bwk, Plan9 awk), but required in others (busybox awk)].

But the same could be done with shell arithmetic expansion as well:

Code:

printf '%*s\n' $(((COLUMNS+${#msg})/2)) "$msg"

scasey · 07-26-2020, 12:09 PM

^^Very cool!

rnturn · 07-27-2020, 10:36 AM

Quote:

Originally Posted by billlove

No help what so ever - not what I expected but not surprised - so long LinuxQuestions.org

After fixing your glaring typo, your script worked on my system. What sort of help were you looking for?