I wish to print out the first two characters from $TEXT
4
I want my program to print out the text that I typed followed by the first two characters of that text. Is there any way to do this?
#!/bin/bash
#
# Get text from user repeatedly
#
echo "Type away..."
while read TEXT
do
echo You typed $TEXT
if [ "$TEXT" = "quit" ] || [ "$TEXT" = "q" ] || [ "$TEXT" = "Q" ] || [ "$TEXT" = "QUIT" ]; then
echo So I quit!
exit 0
fi
done
echo "HELP!"
bash shell-script variable
edited Dec 4 '18 at 21:00
wjandrea
466413
asked Dec 4 '18 at 14:56
The Real Fawcett
254
add a comment |
4
I want my program to print out the text that I typed followed by the first two characters of that text. Is there any way to do this?
#!/bin/bash
#
# Get text from user repeatedly
#
echo "Type away..."
while read TEXT
do
echo You typed $TEXT
if [ "$TEXT" = "quit" ] || [ "$TEXT" = "q" ] || [ "$TEXT" = "Q" ] || [ "$TEXT" = "QUIT" ]; then
echo So I quit!
exit 0
fi
done
echo "HELP!"
bash shell-script variable
edited Dec 4 '18 at 21:00
wjandrea
466413
asked Dec 4 '18 at 14:56
The Real Fawcett
254
1
ALthough I don't understand the question entirely. If you typefoobarwhat would you want to see?foorarorfoobarar?
– Valentin Bajrami
Dec 4 '18 at 15:14
add a comment |
4
4
4
I want my program to print out the text that I typed followed by the first two characters of that text. Is there any way to do this?
#!/bin/bash
#
# Get text from user repeatedly
#
echo "Type away..."
while read TEXT
do
echo You typed $TEXT
if [ "$TEXT" = "quit" ] || [ "$TEXT" = "q" ] || [ "$TEXT" = "Q" ] || [ "$TEXT" = "QUIT" ]; then
echo So I quit!
exit 0
fi
done
echo "HELP!"
bash shell-script variable
edited Dec 4 '18 at 21:00
wjandrea
466413
asked Dec 4 '18 at 14:56
The Real Fawcett
254
I want my program to print out the text that I typed followed by the first two characters of that text. Is there any way to do this?
#!/bin/bash
#
# Get text from user repeatedly
#
echo "Type away..."
while read TEXT
do
echo You typed $TEXT
if [ "$TEXT" = "quit" ] || [ "$TEXT" = "q" ] || [ "$TEXT" = "Q" ] || [ "$TEXT" = "QUIT" ]; then
echo So I quit!
exit 0
fi
done
echo "HELP!"
bash shell-script variable
bash shell-script variable
edited Dec 4 '18 at 21:00
wjandrea
466413
asked Dec 4 '18 at 14:56
The Real Fawcett
254
edited Dec 4 '18 at 21:00
wjandrea
466413
asked Dec 4 '18 at 14:56
The Real Fawcett
254
edited Dec 4 '18 at 21:00
wjandrea
466413
edited Dec 4 '18 at 21:00
wjandrea
466413
edited Dec 4 '18 at 21:00
wjandrea
466413
466413
asked Dec 4 '18 at 14:56
The Real Fawcett
254
asked Dec 4 '18 at 14:56
The Real Fawcett
254
asked Dec 4 '18 at 14:56
The Real Fawcett
254
254
1
ALthough I don't understand the question entirely. If you typefoobarwhat would you want to see?foorarorfoobarar?
– Valentin Bajrami
Dec 4 '18 at 15:14
add a comment |
1
ALthough I don't understand the question entirely. If you typefoobarwhat would you want to see?foorarorfoobarar?
– Valentin Bajrami
Dec 4 '18 at 15:14
1
1
ALthough I don't understand the question entirely. If you type
foobar what would you want to see? fo or ar or foobarar?– Valentin Bajrami
Dec 4 '18 at 15:14
ALthough I don't understand the question entirely. If you type
foobar what would you want to see? fo or ar or foobarar?– Valentin Bajrami
Dec 4 '18 at 15:14
add a comment |
2 Answers
2
active
oldest
votes
9
You can get the first characters using notation like ${var:0:N} where var is the variable name and N is number of characters you want. So, for your question, ${TEXT:0:2} should give you the first two characters in TEXT. Example:
TEXT="Some text"
echo "$TEXT: '$TEXT', first 2 chars: '${TEXT:0:2}'"
Output:
$TEXT: 'Some text', first 2 chars: 'So'
The Linux Documentation Project has a chapter called "Manipulating Strings". The "substring extraction" section has more details about this notation.
edited Dec 4 '18 at 20:09
ilkkachu
56.3k784156
answered Dec 4 '18 at 15:06
GreenMatt
22917
add a comment |
4
Just to provide you a general idea. In your case you can use case... esac construction. An example shown here
#!/usr/bin/env bash
call_for_help()
{
echo "Please help!" >&2
}
if (($# < 1)); then
call_for_help
fi
while read -rp "Type away: " TEXT;
do
echo "${TEXT:0:2}"
case "$TEXT" in
[qQ] | [Qq]uit)
echo "You quited"
exit 1
;;
esac
done
answered Dec 4 '18 at 15:11
Valentin Bajrami
5,90611627
1
(1) I applaud the use ofcase…esacand the[Ww][Oo][Rr][Dd]notation, but you should probably state that your code is not functionally equivalent to the OP's. The OP's script will recognize onlyq,Q,quitandQUIT; yours will recognize those and alsoQuit,qUIT,quIt, and 11 other variants. (2) The whole point of sayingwhile read ……doinstead ofwhile true...do read …is to have the loop end when thereadfails, as happens when it reads an EOF (end of a file, or Ctrl+D on a terminal). … (Cont’d)
– G-Man
Dec 4 '18 at 23:34
1
(Cont’d) … By injecting theechostatements between thereadand thedo, you create a loop that cannot be terminated by Ctrl+D (and will spin forever if given input from a file). (3) So it's adding insult to injury that your code doesn't quit when the user tells it to! (4) Why are you displaying the last two characters of the input? (5) Why are you treating the input as an array? (6) What's this about$OPTARG?
– G-Man
Dec 4 '18 at 23:34
@G-Man I think your comments are very valid indeed. The last line$OPTARGwill of course be valid only whengetoptsis used. Also I put there 2 options (array var and the other one) since the question wasn't clear what OP wanted. Furthermore, it is indeed pointless to have the variable there in between. I'm going to make some changes so others aren't confused! Thanks for the comments
– Valentin Bajrami
Dec 5 '18 at 8:35
add a comment |
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2 Answers
2
active
oldest
votes
2 Answers
2
active
oldest
votes
active
oldest
votes
active
oldest
votes
9
You can get the first characters using notation like ${var:0:N} where var is the variable name and N is number of characters you want. So, for your question, ${TEXT:0:2} should give you the first two characters in TEXT. Example:
TEXT="Some text"
echo "$TEXT: '$TEXT', first 2 chars: '${TEXT:0:2}'"
Output:
$TEXT: 'Some text', first 2 chars: 'So'
The Linux Documentation Project has a chapter called "Manipulating Strings". The "substring extraction" section has more details about this notation.
edited Dec 4 '18 at 20:09
ilkkachu
56.3k784156
answered Dec 4 '18 at 15:06
GreenMatt
22917
add a comment |
9
You can get the first characters using notation like ${var:0:N} where var is the variable name and N is number of characters you want. So, for your question, ${TEXT:0:2} should give you the first two characters in TEXT. Example:
TEXT="Some text"
echo "$TEXT: '$TEXT', first 2 chars: '${TEXT:0:2}'"
Output:
$TEXT: 'Some text', first 2 chars: 'So'
The Linux Documentation Project has a chapter called "Manipulating Strings". The "substring extraction" section has more details about this notation.
edited Dec 4 '18 at 20:09
ilkkachu
56.3k784156
answered Dec 4 '18 at 15:06
GreenMatt
22917
add a comment |
9
9
9
You can get the first characters using notation like ${var:0:N} where var is the variable name and N is number of characters you want. So, for your question, ${TEXT:0:2} should give you the first two characters in TEXT. Example:
TEXT="Some text"
echo "$TEXT: '$TEXT', first 2 chars: '${TEXT:0:2}'"
Output:
$TEXT: 'Some text', first 2 chars: 'So'
The Linux Documentation Project has a chapter called "Manipulating Strings". The "substring extraction" section has more details about this notation.
edited Dec 4 '18 at 20:09
ilkkachu
56.3k784156
answered Dec 4 '18 at 15:06
GreenMatt
22917
You can get the first characters using notation like ${var:0:N} where var is the variable name and N is number of characters you want. So, for your question, ${TEXT:0:2} should give you the first two characters in TEXT. Example:
TEXT="Some text"
echo "$TEXT: '$TEXT', first 2 chars: '${TEXT:0:2}'"
Output:
$TEXT: 'Some text', first 2 chars: 'So'
The Linux Documentation Project has a chapter called "Manipulating Strings". The "substring extraction" section has more details about this notation.
edited Dec 4 '18 at 20:09
ilkkachu
56.3k784156
answered Dec 4 '18 at 15:06
GreenMatt
22917
edited Dec 4 '18 at 20:09
ilkkachu
56.3k784156
edited Dec 4 '18 at 20:09
ilkkachu
56.3k784156
edited Dec 4 '18 at 20:09
ilkkachu
56.3k784156
56.3k784156
answered Dec 4 '18 at 15:06
GreenMatt
22917
answered Dec 4 '18 at 15:06
GreenMatt
22917
answered Dec 4 '18 at 15:06
GreenMatt
22917
22917
add a comment |
add a comment |
4
Just to provide you a general idea. In your case you can use case... esac construction. An example shown here
#!/usr/bin/env bash
call_for_help()
{
echo "Please help!" >&2
}
if (($# < 1)); then
call_for_help
fi
while read -rp "Type away: " TEXT;
do
echo "${TEXT:0:2}"
case "$TEXT" in
[qQ] | [Qq]uit)
echo "You quited"
exit 1
;;
esac
done
answered Dec 4 '18 at 15:11
Valentin Bajrami
5,90611627
1
(1) I applaud the use ofcase…esacand the[Ww][Oo][Rr][Dd]notation, but you should probably state that your code is not functionally equivalent to the OP's. The OP's script will recognize onlyq,Q,quitandQUIT; yours will recognize those and alsoQuit,qUIT,quIt, and 11 other variants. (2) The whole point of sayingwhile read ……doinstead ofwhile true...do read …is to have the loop end when thereadfails, as happens when it reads an EOF (end of a file, or Ctrl+D on a terminal). … (Cont’d)
– G-Man
Dec 4 '18 at 23:34
1
(Cont’d) … By injecting theechostatements between thereadand thedo, you create a loop that cannot be terminated by Ctrl+D (and will spin forever if given input from a file). (3) So it's adding insult to injury that your code doesn't quit when the user tells it to! (4) Why are you displaying the last two characters of the input? (5) Why are you treating the input as an array? (6) What's this about$OPTARG?
– G-Man
Dec 4 '18 at 23:34
@G-Man I think your comments are very valid indeed. The last line$OPTARGwill of course be valid only whengetoptsis used. Also I put there 2 options (array var and the other one) since the question wasn't clear what OP wanted. Furthermore, it is indeed pointless to have the variable there in between. I'm going to make some changes so others aren't confused! Thanks for the comments
– Valentin Bajrami
Dec 5 '18 at 8:35
add a comment |
4
Just to provide you a general idea. In your case you can use case... esac construction. An example shown here
#!/usr/bin/env bash
call_for_help()
{
echo "Please help!" >&2
}
if (($# < 1)); then
call_for_help
fi
while read -rp "Type away: " TEXT;
do
echo "${TEXT:0:2}"
case "$TEXT" in
[qQ] | [Qq]uit)
echo "You quited"
exit 1
;;
esac
done
answered Dec 4 '18 at 15:11
Valentin Bajrami
5,90611627
1
(1) I applaud the use ofcase…esacand the[Ww][Oo][Rr][Dd]notation, but you should probably state that your code is not functionally equivalent to the OP's. The OP's script will recognize onlyq,Q,quitandQUIT; yours will recognize those and alsoQuit,qUIT,quIt, and 11 other variants. (2) The whole point of sayingwhile read ……doinstead ofwhile true...do read …is to have the loop end when thereadfails, as happens when it reads an EOF (end of a file, or Ctrl+D on a terminal). … (Cont’d)
– G-Man
Dec 4 '18 at 23:34
1
(Cont’d) … By injecting theechostatements between thereadand thedo, you create a loop that cannot be terminated by Ctrl+D (and will spin forever if given input from a file). (3) So it's adding insult to injury that your code doesn't quit when the user tells it to! (4) Why are you displaying the last two characters of the input? (5) Why are you treating the input as an array? (6) What's this about$OPTARG?
– G-Man
Dec 4 '18 at 23:34
@G-Man I think your comments are very valid indeed. The last line$OPTARGwill of course be valid only whengetoptsis used. Also I put there 2 options (array var and the other one) since the question wasn't clear what OP wanted. Furthermore, it is indeed pointless to have the variable there in between. I'm going to make some changes so others aren't confused! Thanks for the comments
– Valentin Bajrami
Dec 5 '18 at 8:35
add a comment |
4
4
4
Just to provide you a general idea. In your case you can use case... esac construction. An example shown here
#!/usr/bin/env bash
call_for_help()
{
echo "Please help!" >&2
}
if (($# < 1)); then
call_for_help
fi
while read -rp "Type away: " TEXT;
do
echo "${TEXT:0:2}"
case "$TEXT" in
[qQ] | [Qq]uit)
echo "You quited"
exit 1
;;
esac
done
answered Dec 4 '18 at 15:11
Valentin Bajrami
5,90611627
Just to provide you a general idea. In your case you can use case... esac construction. An example shown here
#!/usr/bin/env bash
call_for_help()
{
echo "Please help!" >&2
}
if (($# < 1)); then
call_for_help
fi
while read -rp "Type away: " TEXT;
do
echo "${TEXT:0:2}"
case "$TEXT" in
[qQ] | [Qq]uit)
echo "You quited"
exit 1
;;
esac
done
answered Dec 4 '18 at 15:11
Valentin Bajrami
5,90611627
edited Dec 5 '18 at 8:38
answered Dec 4 '18 at 15:11
Valentin Bajrami
5,90611627
answered Dec 4 '18 at 15:11
Valentin Bajrami
5,90611627
answered Dec 4 '18 at 15:11
Valentin Bajrami
5,90611627
5,90611627
1
(1) I applaud the use ofcase…esacand the[Ww][Oo][Rr][Dd]notation, but you should probably state that your code is not functionally equivalent to the OP's. The OP's script will recognize onlyq,Q,quitandQUIT; yours will recognize those and alsoQuit,qUIT,quIt, and 11 other variants. (2) The whole point of sayingwhile read ……doinstead ofwhile true...do read …is to have the loop end when thereadfails, as happens when it reads an EOF (end of a file, or Ctrl+D on a terminal). … (Cont’d)
– G-Man
Dec 4 '18 at 23:34
1
(Cont’d) … By injecting theechostatements between thereadand thedo, you create a loop that cannot be terminated by Ctrl+D (and will spin forever if given input from a file). (3) So it's adding insult to injury that your code doesn't quit when the user tells it to! (4) Why are you displaying the last two characters of the input? (5) Why are you treating the input as an array? (6) What's this about$OPTARG?
– G-Man
Dec 4 '18 at 23:34
@G-Man I think your comments are very valid indeed. The last line$OPTARGwill of course be valid only whengetoptsis used. Also I put there 2 options (array var and the other one) since the question wasn't clear what OP wanted. Furthermore, it is indeed pointless to have the variable there in between. I'm going to make some changes so others aren't confused! Thanks for the comments
– Valentin Bajrami
Dec 5 '18 at 8:35
add a comment |
1
(1) I applaud the use ofcase…esacand the[Ww][Oo][Rr][Dd]notation, but you should probably state that your code is not functionally equivalent to the OP's. The OP's script will recognize onlyq,Q,quitandQUIT; yours will recognize those and alsoQuit,qUIT,quIt, and 11 other variants. (2) The whole point of sayingwhile read ……doinstead ofwhile true...do read …is to have the loop end when thereadfails, as happens when it reads an EOF (end of a file, or Ctrl+D on a terminal). … (Cont’d)
– G-Man
Dec 4 '18 at 23:34
1
(Cont’d) … By injecting theechostatements between thereadand thedo, you create a loop that cannot be terminated by Ctrl+D (and will spin forever if given input from a file). (3) So it's adding insult to injury that your code doesn't quit when the user tells it to! (4) Why are you displaying the last two characters of the input? (5) Why are you treating the input as an array? (6) What's this about$OPTARG?
– G-Man
Dec 4 '18 at 23:34
@G-Man I think your comments are very valid indeed. The last line$OPTARGwill of course be valid only whengetoptsis used. Also I put there 2 options (array var and the other one) since the question wasn't clear what OP wanted. Furthermore, it is indeed pointless to have the variable there in between. I'm going to make some changes so others aren't confused! Thanks for the comments
– Valentin Bajrami
Dec 5 '18 at 8:35
1
1
(1) I applaud the use of
case…esac and the [Ww][Oo][Rr][Dd] notation, but you should probably state that your code is not functionally equivalent to the OP's. The OP's script will recognize only q, Q, quit and QUIT; yours will recognize those and also Quit, qUIT, quIt, and 11 other variants. (2) The whole point of saying while read … … do instead of while true ... do read … is to have the loop end when the read fails, as happens when it reads an EOF (end of a file, or Ctrl+D on a terminal). … (Cont’d)– G-Man
Dec 4 '18 at 23:34
(1) I applaud the use of
case…esac and the [Ww][Oo][Rr][Dd] notation, but you should probably state that your code is not functionally equivalent to the OP's. The OP's script will recognize only q, Q, quit and QUIT; yours will recognize those and also Quit, qUIT, quIt, and 11 other variants. (2) The whole point of saying while read … … do instead of while true ... do read … is to have the loop end when the read fails, as happens when it reads an EOF (end of a file, or Ctrl+D on a terminal). … (Cont’d)– G-Man
Dec 4 '18 at 23:34
1
1
(Cont’d) … By injecting the
echo statements between the read and the do, you create a loop that cannot be terminated by Ctrl+D (and will spin forever if given input from a file). (3) So it's adding insult to injury that your code doesn't quit when the user tells it to! (4) Why are you displaying the last two characters of the input? (5) Why are you treating the input as an array? (6) What's this about $OPTARG?– G-Man
Dec 4 '18 at 23:34
(Cont’d) … By injecting the
echo statements between the read and the do, you create a loop that cannot be terminated by Ctrl+D (and will spin forever if given input from a file). (3) So it's adding insult to injury that your code doesn't quit when the user tells it to! (4) Why are you displaying the last two characters of the input? (5) Why are you treating the input as an array? (6) What's this about $OPTARG?– G-Man
Dec 4 '18 at 23:34
@G-Man I think your comments are very valid indeed. The last line
$OPTARG will of course be valid only when getopts is used. Also I put there 2 options (array var and the other one) since the question wasn't clear what OP wanted. Furthermore, it is indeed pointless to have the variable there in between. I'm going to make some changes so others aren't confused! Thanks for the comments– Valentin Bajrami
Dec 5 '18 at 8:35
@G-Man I think your comments are very valid indeed. The last line
$OPTARG will of course be valid only when getopts is used. Also I put there 2 options (array var and the other one) since the question wasn't clear what OP wanted. Furthermore, it is indeed pointless to have the variable there in between. I'm going to make some changes so others aren't confused! Thanks for the comments– Valentin Bajrami
Dec 5 '18 at 8:35
add a comment |
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1
ALthough I don't understand the question entirely. If you type
foobarwhat would you want to see?foorarorfoobarar?– Valentin Bajrami
Dec 4 '18 at 15:14