02-10-2020
Well, that's interesting. I see from searching for "File Descriptor" that it refers to an integer that in turn refers to a 'file' (or a byte stream) for a process on a Unix system. I guess the only other thing I would like to know now is how to know whether the "&" is needed at a particular point on the command line. As we have it "2" indicated stderr, but "1" indicated a file named 1, and "&1" indicated stdout. How would I know when to include "&"?
10 More Discussions You Might Find Interesting
1. UNIX for Dummies Questions & Answers
see this
cat < Files
return the cointent of Files
but
cat files
return the same result
WHI???
this command
lp -f """PRINTER" < cat files
not print the content of files (1 Reply)
Discussion started by: ZINGARO
1 Replies
2. Shell Programming and Scripting
Dear friends,
please tell me how to find the files which are existing in the current directory, but it sholud not search in the sub directories..
it is like this,
current directory contains
file1, file2, file3, dir1, dir2
and dir1 conatins
file4, file5
and dir2 contains
file6,... (9 Replies)
Discussion started by: swamymns
9 Replies
3. Shell Programming and Scripting
I intend to find the path/full location of a file(filename given by user thru "read filenme") using "find" or any other command and then store it's output in a variable for some other processing.
But struggling to put all things together (i.e finding the fully qualified location of that file and... (4 Replies)
Discussion started by: punitpa
4 Replies
4. UNIX for Dummies Questions & Answers
When I do a listing in one particular directory (ls -al) I get:
total 43456
drwxrwxrwx 2 root root 4096
drwxrwxrwx 3 root root 4096
-rwxrwxr-x 1 nobody nobody 3701594
-rwxrwxr-x 1 nobody nobody 3108510
-rwxrwxr-x 1 nobody nobody 3070580
-rwxrwxr-x 1 nobody nobody 3099733
-rwxrwxr-x 1... (1 Reply)
Discussion started by: proactiveaditya
1 Replies
5. Shell Programming and Scripting
Hi,
I have line in input file as below:
3G_CENTRAL;INDONESIA_(M)_TELKOMSEL;SPECIAL_WORLD_GRP_7_FA_2_TELKOMSEL
My expected output for line in the file must be :
"1-Radon1-cMOC_deg"|"LDIndex"|"3G_CENTRAL|INDONESIA_(M)_TELKOMSEL"|LAST|"SPECIAL_WORLD_GRP_7_FA_2_TELKOMSEL"
Can someone... (7 Replies)
Discussion started by: shis100
7 Replies
6. Shell Programming and Scripting
I want to list all files/lines which except those which contain the pattern ' /proc/' OR ' /sys/' (mind the leading blank).
In a first approach I coded:
find / -exec ls -ld {} | grep -v ' /proc/| /sys/' \; > /tmp/list.txt
But this doesn't work. I got an error (under Ubuntu):
grep:... (5 Replies)
Discussion started by: pstein
5 Replies
7. Shell Programming and Scripting
Hi All,
I am new here but I have a scripting question that I can't seem to figure out with the "find" cmd.
What I am trying to do is to only have to run a single find cmd parsing the directories and output the different file types to induvidual files and I have been running into problems.... (3 Replies)
Discussion started by: swaters
3 Replies
8. Shell Programming and Scripting
Which one of the following are more accurate and why?
nohup myScript.sh 1>nohup_$(date +%Y%m%d%H%M%S).out 2>&1 &
nohup myScript.sh 1>>nohup_$(date +%Y%m%d%H%M%S).out 2>&1 &
nohup myScript.sh >nohup_$(date +%Y%m%d%H%M%S).out 2>&1 &
nohup myScript.sh >>nohup_$(date +%Y%m%d%H%M%S).out 2>&1 &... (3 Replies)
Discussion started by: kchinnam
3 Replies
9. UNIX for Dummies Questions & Answers
How to use "mailx" command to do e-mail reading the input file containing email address, where column 1 has name and column 2 containing “To” e-mail address
and column 3 contains “cc” e-mail address to include with same email.
Sample input file, email.txt
Below is an sample code where... (2 Replies)
Discussion started by: asjaiswal
2 Replies
10. Programming
Hi,
I have to redirect output of the command "perldoc perllocal" to new file which
contains all the perl module installed.
Currently using
perldoc perllocal >> mod_data
This does not contain all perl modules installed locally on machine, and each character is doubled.
Please... (3 Replies)
Discussion started by: asak
3 Replies
LEARN ABOUT ULTRIX
setlinebuf
setbuf(3s) setbuf(3s)
Name
setbuf, setbuffer, setlinebuf, setvbuf - assign buffering to a stream
Syntax
#include <stdio.h>
void setbuf(stream, buf)
FILE *stream;
char *buf;
void setbuffer(stream, buf, size)
FILE *stream;
char *buf;
int size;
void setlinebuf(stream)
FILE *stream;
int setvbuf(stream, buf, type, size)
FILE *stream;
char *buf;
int type; size_t size;
Description
The three types of buffering available are unbuffered, block buffered, and line buffered. When an output stream is unbuffered, information
appears on the destination file or terminal as soon as written; when it is block buffered many characters are saved up and written as a
block; when it is line buffered characters are saved up until a new line is encountered or input is read from stdin. The routine may be
used to force the block out early. Normally all files are block buffered. For further information, see A buffer is obtained from upon the
first or on the file. If the standard stream stdout refers to a terminal it is line buffered. The standard stream stderr is always
unbuffered.
The routine is used after a stream has been opened but before it is read or written. The character array buf is used instead of an auto-
matically allocated buffer. If buf is the constant pointer NULL, input/output will be completely unbuffered. A manifest constant BUFSIZ
tells how big an array is needed:
char buf[BUFSIZ];
The routine, an alternate form of is used after a stream has been opened but before it is read or written. The character array buf whose
size is determined by the size argument is used instead of an automatically allocated buffer. If buf is the constant pointer NULL,
input/output will be completely unbuffered.
The routine is used to change stdout or stderr from block buffered or unbuffered to line buffered. Unlike and it can be used at any time
that the file descriptor is active.
The routine may be used after a stream has been opened but before it is read or written. Type determines how stream will be buffered.
Legal values for type, defined in stdio.h are:
_IOFBF causes input/output to be fully buffered.
_IOLBF causes output to be line buffered; the buffer will be flushed when a new line is written, the buffer is full, or input is
requested.
_IONBF causes input/output to be completely unbuffered.
If buf is not the NULL pointer, the array it points to will be used for buffering, instead of an automatically allocated buffer. The size
specifies the size of the buffer to be used. The constant BUFSIZ in <stdio.h> is suggested as a good buffer size. If input/output is
unbuffered, buf and size are ignored.
By default, output to a terminal is line buffered and all other input/output is fully buffered.
A file can be changed from unbuffered or line buffered to block buffered by using For further information, see A file can be changed from
block buffered or line buffered to unbuffered by using followed by with a buffer argument of NULL.
Restrictions
The standard error stream should be line buffered by default.
The and functions are not portable to non 4.2 BSD versions of UNIX.
See Also
malloc(3), fclose(3s), fopen(3s), fread(3s), getc(3s), printf(3s), putc(3s), puts(3s).
setbuf(3s)