read

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read NAME waits for a line and stores it in NAME. With more names, the words are split: the first word to the first name, the rest to the last one. With no name the line goes to $REPLY. while read -r LINE; do …; done < FILE is the standard way to process a file line by line.

طريقة الكتابة

read [-ers] [-a ARRAY] [-d DELIM] [-i TEXT] [-n N] [-N N] [-p PROMPT] [-t TIMEOUT] [-u FD] [NAME]...

الخيارات 11

الأكثر استخدامًا

-p PROMPT: Show a prompt first.
-r: Backslashes are normal characters (use it almost always).
-s: Silent: do not show the typed text (passwords).
-t SECONDS: Give up after this time.
-n N: Return after N characters.
-N N: Read exactly N characters.
-a ARRAY: Store the words in an array.
-d DELIM: Read until this character instead of a newline.
-e: Use readline (editing keys) in a terminal.
-i TEXT: Default text for -e.
-u FD: Read from this file descriptor.

أمثلة 10

$ مستخدم عادي# بصلاحية root (أو مع sudo)

1Ask a question

$read -p "Your name: " NAME; echo "Hello $NAME"

Simple input in scripts.

2Ask for a password
```
$read -s -p "Password: " PASS; echo
```
Nothing is shown while typing.

3Process a file line by line

$while read -r LINE; do echo "line: $LINE"; done < /etc/hostname

-r keeps backslashes.

4Split fields

$echo "anna sales 3000" | { read -r NAME GROUP GID; echo "$NAME is in $GROUP ($GID)"; }

Words go to the names in order.

5Split /etc/passwd fields

$while IFS=: read -r USER _ UID _; do [ "$UID" -ge 1000 ] && echo "$USER"; done < /etc/passwd

IFS=: splits on colons.

6Yes/no with a timeout

$read -t 10 -n 1 -p "Continue? [y/N] " ANSWER; echo; [ "$ANSWER" = y ] || exit 1

Defaults to no after 10 seconds.

7Into an array

$read -r -a PARTS <<< "a b c"; echo "${PARTS[1]}"
b

Index starts at 0.

8Read command output (not a pipe into while)
```
$while read -r PID CMD; do echo "$PID $CMD"; done < <(ps -eo pid=,comm= | head -3)
```
Process substitution keeps variables after the loop.
9Default value with editing
```
$read -e -i "/backup" -p "Target folder: " DIR
```
The user can edit the default.
10Pause a script
```
$read -r -p "Press Enter to continue"
```
Waits for Enter.

انتبه

Without -r, backslashes in the input disappear.
cmd | while read … runs the loop in a subshell: variables set inside are gone afterwards.

رموز الخروج

0 :: A line was read. 1 :: End of file (or timeout > 128 with -t).

`read`

ماذا يفعل

طريقة الكتابة

الخيارات 11

أمثلة 10

1Ask a question

2Ask for a password

3Process a file line by line

4Split fields

5Split /etc/passwd fields

6Yes/no with a timeout

7Into an array

8Read command output (not a pipe into while)

9Default value with editing

10Pause a script

انتبه

رموز الخروج

الدليل الكامل

ماذا يفعل

طريقة الكتابة

الخيارات 11

أمثلة 10

1Ask a question

2Ask for a password

3Process a file line by line

4Split fields

5Split /etc/passwd fields

6Yes/no with a timeout

7Into an array

8Read command output (not a pipe into while)

9Default value with editing

10Pause a script

انتبه

رموز الخروج

أوامر مرتبطة

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الدليل الكامل

`read`