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6
votes
4answers
11k views

printing colored text using echo

I know that for printing a colored text using echo, for example red color, the code is: echo -e "\e[1;31m This is red text \e[0m" and I know that in this example, 31 is code of red color and the ...
6
votes
2answers
4k 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 ...
6
votes
1answer
344 views

differences between echo“”> and > command

I am new to Linux. There is something that is unclear to me. What is the difference between echo "" > logfile and > logfile ? When I run the first one, the logfile size doesn't become zero ...
2
votes
2answers
4k views

How can I trim the carriage return from text that is being piped in bash?

I'm using this command to get my last typed command: history | cut -c 8- | tail -n 2 | head -n 1 It works very well in bash, removing the line numbers, but there is one problem I have with it, (er, ...
7
votes
4answers
3k views

How can I create a file with multiple lines from the command-line?

How can I enter the following contents in a file: Hi abcd I tried using echo "Hi\nabcd" >> ab.txt, but in the file it's written as is (the \n is included, instead of a newline)
3
votes
1answer
318 views

Shell script doesn't paint last line of stdout to screen without user input

I have a shell script that's happily doing all my backup process and writing progress to stderr and stdout, with one exception — the last line doesn't get written to my terminal (if I call the script ...
1
vote
2answers
1k views

Alias Loop in csh

Why is there an Alias loop error created here: alias df 'printf "\n"; df -hP | column -t' But not here: alias df 'df -hP | column -t' I realize I could call the alias something else and still ...
13
votes
4answers
9k views

How to delete line with echo?

I know that I could delete the last three chars with: echo -ne '\b\b\b' But how can I delete a full line? I mean I dont want to use: echo -ne ...
3
votes
1answer
107 views

Why doesn't text piped into an echo get outputted?

Why doesn't this command output "1"? echo 1 | echo I imagine it working this way: 1. echo 1 (outputs 1) 2. | echo (takes the 1 as an input, then echos it) Isn't this what should happen?
4
votes
4answers
8k views

Why is echo ignoring my quote characters?

The echo command isn't including the complete text that I give it. For example, if I do: $ echo ' echo PARAM=` grep $ARG /var/tmp/setfile | awk '{print $2}' ` ' It outputs: echo PARAM=` ...
1
vote
2answers
520 views

How can I right-justify variable length output?

So I don't want this: echo "9" 9 Rather I need this, with e.g.: 4 spaces before it: MAGICK "9" 9 So if I try it with 10: MAGICK "10" 10 then it will just have 3 spaces before it. How ...
-1
votes
2answers
388 views

Copying a few lines from stdout to stderr - but only if stderr is different from stdout

I have a bash script "backup.sh", which prints out everything to stdout, including all the files that are transferred during backup. I'd like to make it possible to keep that full output, but when ...
3
votes
2answers
319 views

Weird output by echo

I was playing with echo $$ a while back. Well that displays that pid of the shell. But then I did echo ! which promptly displayed !. Then echo !! produced echo echo ! echo ! $echo !!! gave echo ...
23
votes
4answers
4k views

How to echo a bang!

I tried to create a script by echo'ing the contents into a file, instead of opening it with a editor echo -e "#!/bin/bash \n /usr/bin/command args" > .scripts/command The output: bash: ...