cat is a Unix utility used for concatenating files.

learn more… | top users | synonyms

1
vote
1answer
83 views

Difference between cat * and cat * >>

To merge multiple files in a dir I have tried: cat * myfile.log but this seems to just merge line and line and is thus very slow So using instead: cat * >> bigfile merges the files much ...
0
votes
1answer
23 views

removing the last line of a file not working? [duplicate]

I have this TXT file that is created by a bash script and at the end I want to remove the last line of that file that is an empty one. head --lines=-1 r3.txt > r4.txt sed '$d' r3.txt > r4.txt ...
0
votes
0answers
28 views

cat echoes to serial port

Connecting my Windows PC to a Linux system (Wheezy) via the serial port (RS232) basically works except one problem when sending a message from the the PC terminal the Linux system. The reception of ...
4
votes
1answer
141 views

How can I get less or cat to use color in the output from .cat of my .bashrc, similar to vi 'ing it?

When I vi my .bashrc file it is colorized, i.e. but when I cat or less the file I get all white, i.e. How can I get cat (and less) to have color? cat does have color for my ruby .rb files but ...
4
votes
2answers
105 views

Spliting `File` and `directory name with space' via shell script

I've got a file called Files.txt having following content: TestApp/Resources/Supporting Files/main.m TestApp/Resources/Supporting Files/AppDelegate.h TestApp/Resources/Supporting Files/AppDelegate.m ...
5
votes
1answer
104 views

Why does “cat ttyUSB0” not produce output?

I connected an infrared receiver to a USB port ... (the last line of dmesg tells device file) $ dmesg [10496.596063] usb 7-2: new full-speed USB device number 2 using uhci_hcd [10496.751112] usb 7-2: ...
1
vote
2answers
67 views

Why using cat on binary files messed up the terminal and how?

If I understand correctly the cat manual: concatenate files and print on the standard output cat will take files as argument and print them on standard output. What I don't get is if I use the ...
9
votes
2answers
845 views

Fastest way to concatenate files

I've got 10k+ files totaling over 20GB that I need to concatenate into one file. Is there a faster way than cat input_file* >> out ? The preferred way would be a bash command, Python is ...
2
votes
1answer
58 views

< and << in UNIX /Linux

What is the option <<and < are used in linux for??? For example cat << abc.txt I know its a stupid question, but i was not able to search it on google as i did not know what ...
1
vote
1answer
51 views

Cat and Less give different output

I executed the following command # top > /home/user/top_output.txt Nothing Happened for a while and then i pressed Ctrl+C. When i checked the file that was created, it had the contents in it. So ...
1
vote
2answers
101 views

How can I get the tac command on OS X?

I like to use tac to reverse the output of cat. However, it's not available in the Mavericks terminal. I tried to find it on MacPorts and again it's not available. Can anyone please show me how to get ...
0
votes
2answers
68 views

How can I concatenate all files in a directory together in one command line operation? [duplicate]

I have 1000 csv files in a directory. I would like to concatenate them all together in order. They are named img_size_1.csv to approx img_size_1000.csv This answer is close but assumes a list file. ...
7
votes
4answers
264 views

Grep from the end of a file to the beginning

I have a file with about 30.000.000 lines (Radius Accounting) and I need to find the last match of a given pattern. The command: tac accounting.log | grep $pattern gives what I need, but it's too ...
2
votes
1answer
135 views

cat file to udp, pt 2: send 1 udp packet per ^C-delimited line

Yesterday I asked a question about catting a file over a UDP socket in bash. The solution we came up was netcat -c -w 1 -v -u -s 127.0.0.1 239.255.0.1 30001 < test.txt. This worked in the sense ...
2
votes
1answer
68 views

cat file to multicast

I have a text file (test.txt) which represents captured network data. The actual protocol is text-based, with NULL line endings, so this isn't a problem. I need to run this test captured data ...
0
votes
1answer
65 views

Passing multiple scripts to shell over ssh

I have a somewhat lengthy script which sources other scripts to include the functions there. I'd like to execute this script remotely via ssh. Now I thought to make one script file of it (without ...
2
votes
3answers
175 views

Can't cat a file or make a directory: contradictory output?

I am getting output from a terminal in Ubuntu 12 that I don't understand. $cat sublime no such file or directory $mkdir sublime cannot create directory 'sublime': File exists How can both of these ...
7
votes
1answer
367 views

How to store an image file in bash variable?

After I use the following command, pngString="$(cat example.png)" echo -n "$pngString" > tmp.png I can't open the tmp.png as a PNG file. Maybe some information is lost when I use $pngString ...
3
votes
2answers
148 views

How to highlight a word in the output of “cat”? [duplicate]

I can do the following to see if some word is available in the output of "cat": cat filename | grep word This filters the output and shows only those lines which contain "word". Now, is it possible ...
8
votes
3answers
326 views

Why does the less-than sign not work as a replacement for cat in bash?

I heard about "useless use of cat" and found some suggestions, but the following outputs nothing in my bash shell. < filename Using cat works as expected though. cat filename I'm using Fedora ...
1
vote
1answer
110 views

Cat write text with “$” inside

I want to write configuration information to a specific file which has dollar signs ($) inside. That seems to be a problem. Here's what I did: $ cat >> /etc/nginx/nginx.conf <<EOF # For ...
2
votes
2answers
202 views

How to mount bzip2-ed Clonezilla image without using extra drive space?

My hard drive seems to be failing and I suspect some data may be already damaged, so I decided to make an entire drive backup with Clonezilla using dd. I have chosen bzip2 compression to fit entire ...
0
votes
2answers
32 views

Concatenate a folder's Java files, with a header for each file

I have an obligation to provide a document which just contains every source code file, with the file's name before each file. Example: ============================= src/com/example/Factory.java ...
3
votes
4answers
122 views

saving output of another command

I need to select certain lines from the log file and also save them to a text file. I tried the following but none of them are working as expected. The file "todel.txt" shows 0 bytes. tail -f ...
3
votes
1answer
89 views

How can i colorize cat output including unknown filetypes in b&w?

I like the colors I have in vim. Can I get my output similarly colorized when I do a cat? I like that I can use the colorize tool as in Colorized `cat` for source and script files?. I would like that ...
0
votes
0answers
37 views

How to `cat` file with syntax highlight? [duplicate]

In my hello.c: /* Hello World program */ #include main() { printf("Hello World"); } How can i cat this file on terminal with syntax highlight?
4
votes
1answer
523 views

How to echo variables using cat into file?

I have simple script like this: #!/bin/bash BOO=bla-bla-bla cat > ./Makefile <<'EOF' Hello INCLUDES := -I/data/opt/include/ -Ideps/ -I$BOO/include EOF Yet it outputs into ...
2
votes
3answers
125 views

Concatenate files in multiple matching subdirectories

I need to concatenate files based upon the name of the subdirectory they are in. The subdirectories sometimes have duplicates and sometimes don't. The file structure looks like this: RootDir 633 ...
5
votes
2answers
179 views

A virtual file containing the concatenation of other files

Is there a way of creating a filesystem object akin to this: mknod files p cat file1 file2 ... fileN > files but such that it can be seeked in, as if it were a regular file?
16
votes
2answers
424 views

Why does this command create an enormously large file?

I was experimenting today with some append operations and, in my curiosity, ran this (where file1.txt was non-empty and file2.txt was empty): $ cat file1.txt >> file2.txt >> file1.txt ...
6
votes
1answer
441 views

How do you use output redirection in combination with here-documents and cat?

Let's say I have a script that I want to pipe to another command or redirect to a file (piping to sh for the examples). Assume that I'm using bash. I could do it using echo: echo "touch somefile ...
1
vote
2answers
134 views

Why the inconsistency with using cat vs. echo piped to this sed command?

Inspired by this question: sed: N command does not read single line I wanted to understand why there appears to be an inconsistency between the following 2 commands: #1. echo This command produces ...
2
votes
3answers
252 views

hardlink/softlink multiple file to one file

I have many files in a folder. I want to concatenate all these files to a single file. For example cat * > final_file; But this will increase disk space and also will consume time. Is there is a way ...
2
votes
2answers
46 views

No result when using Multiple write file & sed in shell script

I would like to swap variables from old file to new file when I use single line like this cat ../oldFile.html | sed "s@$dayMaxInNew@$dayMaxIn@g" > newFile There's result from newFile. But When ...
1
vote
3answers
130 views

Cat 2 files and avoid duplication of lines

I have the file1 with the following content {"name":"clio5", "value":"13"} {"name":"citroen_c4", "value":"23"} {"name":"citroen_c3", "value":"12"} {"name":"golf4", "value":"16"} {"name":"golf3", ...
2
votes
3answers
219 views

Trying to send HTML mail on mac OSX Mountain Lion

I'm trying to send email with an html file as the body (it's actually a cucumber results report if that matters) or an attachment (if sending it as the body does not work) via the command line I've ...
4
votes
1answer
66 views

How to concat file and a line on-fly?

I would like to send to the stdout entire file + extra line. How to do this nicely? So far I did: for LINE in $(cat $INPUT_FILE) do echo $LINE done echo $EXTRA_LINE How to do this bash way (for ...
1
vote
3answers
126 views

can the “cat” command use multi-processes

I need to merge bunch of files in a directory on a unix box that has 8 cores. I am looking for a fast way to merge these files. The cat command uses only one core... is there a way where I can make it ...
8
votes
3answers
694 views

cat all lines from file, which are after “KEYWORD” [duplicate]

I have a file, with a "KEYWORD" on line number n. How can I print all lines starting from line n+1 until the end? For example, here I would liek to pro=int only lines DDD and EEE AAA BBB CCC KEYWORD ...
2
votes
1answer
1k views

Copy multiple files into one (append, merge) in single invocation without shell redirection?

I'm looking for some sort of a command that I can use, to copy/append multiple files into one; but without shell redirection (I'd like to try it in call_usermodehelper, see similar issue in ...
14
votes
5answers
893 views

Is there a tool that combines zcat and cat transparently?

When handling log files, some end up as gzipped files thanks to logrotate and others not. So when you try something like this: $ zcat * you end up with a command line like zcat xyz.log xyz.log.1 ...
1
vote
2answers
2k views

cat files in current folder and all subfolders [duplicate]

I want to cat a file in current folder and all files in all subfolders (and subsubfolders). Here is my directory structure $ tree . ├── f │   └── foo └── yo I want to cat foo and yo. I've tried ...
2
votes
1answer
2k views

Read log file between two dates

I have to read log file between and my question is how to get only the text in the file wich is between two dates using unix commands? Every line contain date and I want to get the text in the file ...
0
votes
1answer
27 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
118 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 ...
44
votes
7answers
2k 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
107 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 ...
6
votes
3answers
869 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
1k 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 ...
5
votes
3answers
981 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 ...