BASH: Is it possible to take STDIN?

microsoft/linux · 04-17-2006, 06:48 PM

Is it possible to take input from STDIN in bash? I know how to do it in C, C++, and Perl, but is there a way to do it in bash? Or if not, is there a way to execute a command(with variables as parameters) in perl?

Hobbletoe · 04-17-2006, 07:33 PM

Code:

man read

Basically, to read information into a variable (let's say temp_var), you

Code:

read temp_var

If you just use read, information is automatically stored in $REPLY.

perfect_circle · 04-17-2006, 07:35 PM

"Is it possible to take input from STDIN in bash?"

What do you mean? the stdin is the keyboard. You always get stdin.

Do you mean to read the input from a bash script?

microsoft/linux · 04-17-2006, 07:45 PM

no, read the input into a bash script, like cin in c++ or scanf in c

perfect_circle · 04-17-2006, 08:16 PM

Quote:

Originally Posted by microsoft/linux

no, read the input into a bash script, like cin in c++ or scanf in c

then as Hobbletoe already posted "read" will do the job:

Code:

#!/bin/bash

echo -n "What's your name? "
read var1
echo "hello $var1"

microsoft/linux · 04-17-2006, 08:23 PM

ok, thanks one and all

fotoguy · 04-17-2006, 08:35 PM

Or if you want to allow a user to choose different options try a case function:

#!/bin/sh

echo "Enter your command (who, list, or cal)"
read command
case "$command" in
who)
echo "Running who..."
who
;;
list)
echo "Running ls..."
ls
;;
cal)
echo "Running cal..."
cal
;;
*)
echo "Bad command, your choices are: who, list, or cal"
;;
esac
exit 0

roybal · 12-30-2011, 10:53 AM

Use cat to capture stdin from the command line pipe:

cat myfile.txt | myscript.sh

in myscript.sh:

#!/bin/bash
cat - | sed "s/tranform this line/into this line/"

ntubski · 12-30-2011, 04:21 PM

You resurrected a five year old thread to post a Useless Use of Cat

Code:

cat myfile.txt | myscript.sh
myscript.sh < myfile.txt

Code:

#!/bin/bash
cat - | sed "s/tranform this line/into this line/"
sed "s/tranform this line/into this line/"