Sponsored Content
Full Discussion: stdin
Top Forums Programming stdin Post 69262 by marquis on Wednesday 13th of April 2005 12:33:27 PM
Old 04-13-2005
stdin

hi,
how does a program know whether some data are available from stdin?
I would like to make a program which could read its data from stdin
and _if_there_is_nothing_at_stdin_ from a file which name is given
as an argument. If there is nothing in stdin and no filename is given as
argument, the program should quit immediatly (not wait.)

I'm on Linux with gcc (g++ in fact.)

TIA if any idea.
Samuel
 

10 More Discussions You Might Find Interesting

1. Shell Programming and Scripting

echo with stdin

Why doesnt echo output the contents of the file abc.txt as shown below ? chid@athena:~$ cat abc.txt sssss chid@athena:~$ echo < abc.txt chid@athena:~$ (6 Replies)
Discussion started by: systemsb
6 Replies

2. Shell Programming and Scripting

redirect STDIN

can you redirect STDIN with command arguments? I have tried this approach: # ./script -option <argument1> <argument2> 0<$2 # $2: ambiguous redirect Is this possible? (4 Replies)
Discussion started by: prkfriryce
4 Replies

3. Shell Programming and Scripting

Capturing stdin

Hi all, Consider the following situation: - you launch an compiled binary application from inside a unix shell which presents a text-based type user interface where you can input information ... # echo "I am the $SHELL shell" # I am the /bin/bash shell # ./input # ... imagine the binary... (3 Replies)
Discussion started by: domivv
3 Replies

4. Shell Programming and Scripting

Redirecting to stdin

Hi, I'm having trouble with my script. I have to select different choices without any interaction from a menu that looks like : a - xxxxxxxxxxxxxx b - xxxxxxxxxxxxxx c - xxxxxxxxxxxxxx d - xxxxxxxxxxxxxx I tried things like : echo "a" >&0 read < echo "a" but none worked. Any... (4 Replies)
Discussion started by: flame_eagle
4 Replies

5. Programming

How to write to stdin of another program (program A -> [stdin]program B)

Hi, Program A: uses pipe() I am able to read the stdout of PROGAM B (stdout got through system() command) into PROGRAM A using: * child -> dup2(fd, STDOUT_FILENO); -> execl("/path/PROGRAM B", "PROGRAM B", NULL); * parent -> char line; -> read(fd, line, 100); Question: ---------... (1 Reply)
Discussion started by: vvaidyan
1 Replies

6. UNIX for Dummies Questions & Answers

How to write to stdin of another program (program A -> [stdin]program B)

Hi, Program A: uses pipe() I am able to read the stdout of PROGAM B (stdout got through system() command) into PROGRAM A using: * child -> dup2(fd, STDOUT_FILENO); -> execl("/path/PROGRAM B", "PROGRAM B", NULL); * parent -> char line; -> read(fd, line, 100); Question: ---------... (3 Replies)
Discussion started by: vvaidyan
3 Replies

7. Shell Programming and Scripting

Redirecting stdin from fd 3-9?

Hi I'm trying to do something on the bash command line that I will later put into a bash shell script. I'm trying to take a program that reads stdin (using getline) and be able to keep it running in the background and fire "commands" to it. So what I thought I should do was to try taking... (3 Replies)
Discussion started by: niceguyeddie
3 Replies

8. UNIX for Dummies Questions & Answers

stdin redirection

Hello, my C application under unix runs in redirecting stdin to a file. Example:$appli1 <file1. This application waits often on a scanf(). But I would temporarely reassign stdin at the keyboard for waiting a user's answer. So I thought to add system("appli2"); in the code of appli1. In its... (4 Replies)
Discussion started by: cypleen
4 Replies

9. Shell Programming and Scripting

STDIN-perl

Good morning! How do I make the info that someone inputs from @userArray = <STDIN>, a new array? @userArray = <STDIN>; while () { chomp; last if ! /\d/; push(@userArray,$_); } my($sum,$avg) = &sumIt(@userArray); print "Total:$sum\nAverage:$avg\n"; Im... (2 Replies)
Discussion started by: bigben1220
2 Replies

10. UNIX for Dummies Questions & Answers

STDIN and STDOUT

Hallo, i have a script like: if ;then echo "OK" else echo "ERROR $2 is missing" fi; if ;then touch $2 fi; if ;then cat $1 | grep xy > $2 (1 Reply)
Discussion started by: eightball
1 Replies
GIT-HASH-OBJECT(1)						    Git Manual							GIT-HASH-OBJECT(1)

NAME
git-hash-object - Compute object ID and optionally creates a blob from a file SYNOPSIS
git hash-object [-t <type>] [-w] [--path=<file>|--no-filters] [--stdin] [--] <file>... git hash-object [-t <type>] [-w] --stdin-paths [--no-filters] < <list-of-paths> DESCRIPTION
Computes the object ID value for an object with specified type with the contents of the named file (which can be outside of the work tree), and optionally writes the resulting object into the object database. Reports its object ID to its standard output. This is used by git cvsimport to update the index without modifying files in the work tree. When <type> is not specified, it defaults to "blob". OPTIONS
-t <type> Specify the type (default: "blob"). -w Actually write the object into the object database. --stdin Read the object from standard input instead of from a file. --stdin-paths Read file names from stdin instead of from the command-line. --path Hash object as it were located at the given path. The location of file does not directly influence on the hash value, but path is used to determine what Git filters should be applied to the object before it can be placed to the object database, and, as result of applying filters, the actual blob put into the object database may differ from the given file. This option is mainly useful for hashing temporary files located outside of the working directory or files read from stdin. --no-filters Hash the contents as is, ignoring any input filter that would have been chosen by the attributes mechanism, including the end-of-line conversion. If the file is read from standard input then this is always implied, unless the --path option is given. GIT
Part of the git(1) suite Git 1.8.5.3 01/14/2014 GIT-HASH-OBJECT(1)
All times are GMT -4. The time now is 06:56 AM.
Unix & Linux Forums Content Copyright 1993-2022. All Rights Reserved.
Privacy Policy