cat is a Unix utility used for concatenating files.
0
votes
1answer
16 views
UUOC with ssh file transfer
Just wondering; is it possible to skip the cat in
some_command | ssh remote 'cat > outputfile'
? It feels like a UUOC.
3
votes
2answers
49 views
Reading from a serial interface
I have a serial device running which I need to read data from(I have absolutely no control over the device itself) except reading its output; using hyper terminal in Windows I am able to detect a ...
32
votes
5answers
1k views
How safe is it to cat an arbitrary file?
Sometimes when I cat a binary file by mistake, my terminal gets garbled up. Nothing a quick reset can't fix, but couldn't an attacker theoretically create a file that, when displayed on a terminal, ...
0
votes
4answers
55 views
concatenating multiple files with multiple headers
Im trying to concatenate multiple files with multiple headers to have one file with all the information in it for example.
File 1:
Numbers
1
2
3
Letters
A
B
C
File 2:
Numbers
4
5
6
Letters
D
E
...
3
votes
3answers
144 views
tee + cat: use an output several times and then concatenate results
If I call some command, for instance an echo I can use the results from that command in several other commands with tee. Example:
echo "Hello world!" | tee >(command1) >(command2) ...
1
vote
2answers
125 views
Why does pipe not work with cat and locate?
I am trying to perform this:
locate pg_type.h | cat
But this command simply does nothing different than locate pg_type.h
What should I change ? I want to perform cat pg_type.h wherever pg_type.h ...
2
votes
3answers
313 views
How to make bash put prompt on a new line after cat command?
What I get:
host:~ user$ cat example.txt
some texthost:~ stas$
What I want to get:
host:~ user$ cat example.txt
some text
host:~ stas$
Is there a way I can make cat behave like this?
I'm using ...
16
votes
1answer
503 views
How to implement a horizontal cat?
Standard cat concatenates files line by line (row by row, if you will). I find myself needing a horizontal cat command more and more often recently; i.e. a command that takes a list of files and ...
1
vote
2answers
107 views
How do I pass the contents of a file as a command line parameter
I am storing a file path in a file and need to pass the contents of that file as an argument to a shell script, specifically Maven, something like so:
mvn -Dvar_name=(contents of file)
Would this ...
1
vote
1answer
244 views
How to move files with same name and concatenate
My directory structure is given below. I need to move all the folders from Test3 to Test2 and concatenate the files with same names
[jg@hpc Test2]$ tree
.
|-- Sample_1008
| |-- ...
14
votes
1answer
246 views
Make program first read from pipe, then from keyboard
Consider the interactive program interactive. I have to run this program fairly frequently, and each time I run it the first few commands are the same. Obviously, having to type those commands over ...
3
votes
2answers
92 views
Make ls distinguish scripts from binaries in output
Is it possible to make ls distinguish executable scripts from actual compiled binaries?
The permissions are most often the same (+x), and with ls -F you get an asterisk suffix (*) for both, so it's ...
6
votes
1answer
234 views
Append same text to many files using cat or echo?
How can I write the same content to many text files by using cat or echo in only one command?
For example I want to write "hello" to file1 and file2. I tried:
echo "hello" >> file1 file2
...
1
vote
1answer
233 views
How to tail/grep/awk the last N bytes of a file, rather than lines
I have an application that is logging to a plain text log file (myapp.log) but it doesn't seem to be writing new line characters at the end of each log entry. If I execute a command like tail -n 50 ...
3
votes
3answers
1k views
cat corrupts serial port data
I have an application which writes some bytes to a serial port. When I do cat /dev/ttyS0 to see what is being transferred, I find that the data is corrupted by the cat command. Is there any other way ...
11
votes
6answers
1k views
Command to display first few and last few lines of a file
I have a file with many rows, and each row has a timestamp at the starting, like
[Thread-3] (21/09/12 06:17:38:672) logged message from code.....
So, I frequently check 2 things from this log file.
...
3
votes
1answer
488 views
File size limit exceeded in bash [closed]
I have tried this shell script on a SUSE 10 server, kernel 2.6.16.60, ext3 filesystem.
The script has a line like this:
cat file | awk '{print $1" "$2" "$3}' | sort -n > result
The file's size ...
4
votes
2answers
987 views
Is there a simple command for outputting tab-delimited columns in bash?
E.g. I have a file (produced with echo -e "var1\tvar2\t\var3\tvar4" > foo) that are output (in bash):
$ cat foo
case elems meshing nlsys
uniform 2350 0.076662 2.78
non-conformal ...
6
votes
4answers
3k views
cat line X to line Y on a huge file
Say I have a huge text file (>2GB) and I just want to cat the lines X to Y (e.g. 57890000 to 57890010).
From what I understand I can do this by piping head into tail or viceversa, i.e.
head -A ...
0
votes
1answer
96 views
What is the difference between > and >> (especially as it relates to use with the cat program)?
Suppose that I have a file called temp.txt. Using the cat program, I would like to add the contents of this file to the end of myfile.txt -- creating myfile.txt if it does not exist and appending to ...
3
votes
6answers
575 views
cat files with directory
Is there a command to show the directory/file name when cat files?
For example: assume two files f1.txt and f2.txt are under ./tmp
./tmp/f1.txt
./tmp/f2.txt
Then when I do cat ./tmp/*.txt, only ...
5
votes
3answers
300 views
Gedit or an other non-commandline editor with the ability to spell-check two languages at the same time
I'm searching for an editor with the ability to spell-check two languages at the same time (German and English). Gedit can't do it out of the box.
But I want to use Gedit. It should be possible by ...
0
votes
4answers
715 views
How to pause listing long text file with cat in command prompt after 10lines then press any key
How to pause listing long text file with cat in command prompt after 10lines then press any key.
for example:
cat myfiles.txt
bla
bla
bla
bla
bla
bla
.
.
.
bla
press enter to continue
8
votes
4answers
668 views
Is it possible to merge video files using `cat`?
I wonder if it's possible to merge video files using the cat command? I mean will the resultant file play seamlessly?
3
votes
1answer
502 views
Write data to both a file and a serial port — can I use tee?
I am trying to take the input from a serial port and write it to a file and also then read the file and send it back out the serial port to the host computer. A coworker suggested using the "tee" ...
5
votes
2answers
1k views
Unexpected results testing serial loopback using echo and cat
So I have a standard RS232 serial port that is looped back to itself by simply running a wire from Tx to Rx. I'm testing loopback by running echo and cat in two separate terminals:
cat /dev/ttyS1
...
12
votes
2answers
476 views
How to use `cat` or `less` depending on the line count?
When looking at the content of files, I'd like to automatically cat short files but less those that exceed the screen size. I could use something with wc -l, but is there a better way that maybe also ...
5
votes
2answers
404 views
Why does `cat`ing a file into itself erase it? [duplicate]
Possible Duplicate:
IO redirection and the head command
I just wanted to remove all but the first line of a file. I did this:
head -1 foo.txt
... and verified that I saw only the first ...
3
votes
2answers
2k views
How do I concatenate all the files in a given directory in order of date, where I want the newest file on top?
And with the oldest file on bottom?
Also, if I do this, is it also possible to strip out the redundant headers contained within each HTML file? I'm seeing myself concatenate a lot of HTML files up, ...
3
votes
1answer
146 views
Command substitution: cat with executable content
I have a file called test and the contents are:
ubuntu@regina:~$ cat test
** test **
catting this file via command line works fine, but if I use command substitution I get an understandable but ...
3
votes
3answers
430 views
Colorized `cat` for source and script files? [duplicate]
Possible Duplicate:
How can I display syntax highlighting on a file?
Is there any application like cat, but with color output?
I'd like to view my files with colors like in any IDE's ...
4
votes
4answers
810 views
concatenate two files without adding a newline
If I nano two files, one of which reads 'this' without me entering a newline, and one of which reads 'is' without me entering a newline, I want to be able to then cat the two files together into ...
5
votes
3answers
815 views
Change tab size of “cat” command
When I am in vim I can change the tab size with the following command:
:set ts=4
Is it possible to set tab size for cat command output too?
10
votes
2answers
950 views
How/Why does cat write a bootable ISO to a device
I recently discovered that I can create a bootable USB key from an ISO file by simply using cat (or dd).
I can't find any information on how this works. Why would:
cat my.iso > /dev/sdb ...
2
votes
1answer
110 views
How to cat a file for a certain number of seconds? [duplicate]
Possible Duplicate:
Run a command for a specified time and then abort if time exceeds
Looked all over and I can't find the answer...
Simple question: How can I cat a large file for, lets ...
2
votes
2answers
351 views
Subtracting Binary files
I have 2 Binary Files FileA and FileC
Its is such that FileC = FileA + FileB using the cat utility
How do I subtract FileA from FileC to get FileB ?
PS: I am using Ubuntu Oneiric
6
votes
5answers
856 views
How to avoid a useless use of cat when parsing a file?
I have a file containing a list of directories. For instance
/foo/bar/dir1
/foo/bar/dir2
/foo/bar/dir3
I want to create all these directories. Here's what I did:
for dir in $(cat myfile); do ...
7
votes
8answers
3k views
How can I “cat” a file and remove commented lines?
I'd like to know if there is a way that I could cat file like php.ini and remove all lines starting with ;
For example, if the file contained this:
; - Show all errors, except for notices
;
...
7
votes
3answers
904 views
How can I wrap text at a certain column size?
I know that I can use something like cat test.txt | pr -w 80 to wrap lines to 80 characters wide, but that puts a lot of space on the top and bottom of the printed lines and it does not work right on ...
5
votes
4answers
334 views
Cat with Headers and Line Numbers?
I have files like this
$ cat trapetz
x = 0:0.0001:7pi
plot(x, sin(x).*cos(x))
Area = trapz(x, sin(x).*cos(x))
$ cat simpson
f = inline(sin(x).*cos(x));
Area2 = quad(f, 0, 7pi, 1e-16)
I want ...
0
votes
2answers
468 views
Combination of ls, xargs and zcat leads to duplicate file name suffixes?
Disclaimer: Yes, finding files in a script with ls is bad, but find can't sort by modification date.
Using ls and xargs with echo everything is fine:
$ ls -t1 ssl-access*.gz | xargs -n 1 echo
...
0
votes
1answer
211 views
Running md5sum on a file's contents
md5suming a file is fine, but I cannot seem to invoke md5sum to calculate the hash based only on the file's contents. (For those wondering, I'd prefer that multiple wgets of the same file return the ...
4
votes
5answers
260 views
Conflict between my prompt definition and cat in zsh
I have a file on a remote filesystem that I know has a short text string in it (a sequence of numbers in a single line). If I open the file on a text editor like nano or Emacs I can see the string. ...
22
votes
13answers
2k views
Is there ever a reason to use `cat` when you've got `less`?
I used to use cat to view files. Then I learned that less is usually better, and is a must if the file is longer than a few dozen rows.
My question: Is there ever a reason to use cat instead of less? ...
13
votes
2answers
2k views
How can I display syntax highlighting on a file?
Is there a variant of cat that outputs syntax-highlighted lines of code when used on a source file?
An idea: maybe vi[m] or another editor can be asked to dump the syntax-highlighted contents of said ...
9
votes
2answers
253 views
Weird control-d behavior
I can use cat as a very simple text editor by doing cat > foo.txt.
If I then type:
bar
baz
and then press ctrl+D, it now looks like this:
$ cat > foo.txt
bar
baz^D
with the cursor at the ...
3
votes
2answers
489 views
Performance difference between stdin and command line argument
For some commands, it is possible to specify certain input as either stdin or a command line argument.
Specifically, suppose command can take stdin input and a filename as command line argument, and ...
0
votes
1answer
182 views
Is 'some_program <some_file' faster than 'cat some_file | some_program'? [duplicate]
Possible Duplicate:
Should I care about unnecessary cats?
Both would be functionally equivalent, but when using cat wouldn't it be slower because you have a process first reading the file ...
17
votes
2answers
508 views
Should I care about unnecessary cats?
A lot of command-line utilities can take their input either from a pipe or as a filename argument. For long shell scripts, I find starting the chain off with a cat makes it more readable, especially ...
37
votes
6answers
4k views
dd vs cat — is dd still relevant these days?
I recently realized we can use cat as much as dd, and it's actually faster than dd
I know that dd was useful in dealing with tapes where block size actually mattered in correctness, not just ...
