There are also commands that accept one or more pathname operands or read from standard input, but produce different output when no pathname operands are given. For example, if the command:
produces the output:
the command:
would produce the output:
Compare on your own the output produced by:
for any two text files you may have lying around.
Hi everybody, first of all i am a new member in UNIX.com and this is my first post.
I am impressed with the amount of information a person can ever have in this forum, it is really great having something similiar; anyways let me tell you about the problem I am having, hope you will answer me.... (6 Replies)
Hi,
in my script I need to execute the following command:
query $id 456 432
but it waits for a RETURN character from keyboard and therefore, it fails. I tried something like:
query $id 456 432 << '\n'
but, i'ts clear it is not correct. Is there any way to do this?
Thxs. (0 Replies)
while running a user inter-active program
how can we get the commands from a
file instead of the user?
is there anyway to permanently redirect content
of a file to standard input? (6 Replies)
Hello,
I need to change user and run some commands by using a script.
lets say, I'm using
su - someuser << start
password required -----> how can I enter the password here
command 1
command 2
command 3
command 4
start
While trying to run this I got the following message:
"standard... (2 Replies)
Hello,
I need help with a bash script that I try to improve. I could not find answer so far, maybe because I'm not to familiar with the terminology so feel free to correct my language.
I have a script that looks like:
NODES="node_a node_b node_c"
for NODE in $NODES
do
... (4 Replies)
All,
I have a requirement to write a script where I check for Input redirection when the script was executed, based on which I handle my logic. Below is the example:
my.script
#! /bin/ksh
# Not sure how to frame the if condition below
if ; then
echo "Input Redirected from a file"
... (7 Replies)
Hi,
I am having issues with syntax when I am trying to send a job to the background after a input redirection.
I have this script which sends some files to different servers after zipping them. Once I execute it, it will ask for user input as of which server the files need to go to. (The... (3 Replies)
Hello,
I'm new to Unix (working with OS X 10.8.5) and therefore at the beginning of my adventure. If I ask something stupid, then this is not intentional, but simple nescience. :rolleyes:
I have a problem with the redirection of text file content to echo. I was experimenting with redirection... (6 Replies)
Hi,
#!/bin/bash
while ;
do
rm -f /tmp/pipe
mkfifo /tmp/pipe
./yuv4mpeg_to_v4l2 < /tmp/pipe &
mplayer tom_and_jerry.mp4 -vf scale=480:360 -vo yuv4mpeg:file=/tmp/pipe
sleep 65;
done
When I run this - after mplayer finishes playing video it says - Exiting... (End of... (2 Replies)
Hi,
when I try to redirect input and the command is described as a string within an array redirection does not work. why?
#!/bin/bash
dir=("tail < ./hello.txt")
tail < ./hello.txt #works
${dir} #does not work (2 Replies)
Discussion started by: heinzel
2 Replies
LEARN ABOUT DEBIAN
plan9-cat
CAT(1) General Commands Manual CAT(1)NAME
cat, read, nobs - catenate files
SYNOPSIS
cat [ file ... ]
read [ -m ] [ -n nline ] [ file ... ]
nobs [ file ... ]
DESCRIPTION
Cat reads each file in sequence and writes it on the standard output. Thus
cat file
prints a file and
cat file1 file2 >file3
concatenates the first two files and places the result on the third.
If no file is given, cat reads from the standard input. Output is buffered in blocks matching the input.
Read copies to standard output exactly one line from the named file, default standard input. It is useful in interactive rc(1) scripts.
The -m flag causes it to continue reading and writing multiple lines until end of file; -n causes it to read no more than nline lines.
Read always executes a single write for each line of input, which can be helpful when preparing input to programs that expect line-at-a-
time data. It never reads any more data from the input than it prints to the output.
Nobs copies the named files to standard output except that it removes all backspace characters and the characters that precede them. It is
useful to use as $PAGER with the Unix version of man(1) when run inside a win (see acme(1)) window.
SOURCE
/src/cmd/cat.c
/src/cmd/read.c
/bin/nobs
SEE ALSO cp(1)DIAGNOSTICS
Read exits with status eof on end of file or, in the -n case, if it doesn't read nlines lines.
BUGS
Beware of and which destroy input files before reading them.
CAT(1)