74
votes
3answers
7k views

Why is “echo” so much faster than “touch”?

I'm trying to update the timestamp to the current time on all of the xml files in my directory (recursively). I'm using Mac OSX 10.8.5. On about 300,000 files, the following echo command takes 10 ...
0
votes
3answers
64 views

echo bytes to a file

I'm trying to connect my rasberry Pi to some display using the i2c bus. To get started I wanted to manually write stuff, bytes in particular to a file. How do you write specific bytes to a file? I ...
1
vote
3answers
60 views

Print a message from the left-hand side of a pipe

I want to use a variable from the main shell in a sub shell. I did: export mysql_root_password="test" ( echo $mysql_root_password ) | dialog --gauge "Working hard..." 6 50 But it does not ...
3
votes
2answers
267 views

print command instead of echo in linux

I simply can print a message in terminal using linux echo command. prayag@prayag$ echo "prayag works on JVM" prayag works on JVM Can I have the same output with print command. I actually went ...
6
votes
4answers
346 views

What is the difference between echo `date`, echo “`date`”, and echo '`date`'?

What is the difference between these three commands? echo `date` echo "`date`" echo '`date`' I am confused on what the differences actually are. I think that when the ' are around it means that it ...
2
votes
1answer
205 views

How to echo in shell script without executing the result

I am using this code to print all open files in the specified changelist. while read line; do echo "$line" done < `p4 opened -c $changelist` However, the line also gets executed and I get ...
6
votes
7answers
695 views

timestamp before an echo

Exists a nicer way to create timestamp in front of an echo? Currently I do it this way: #!/bin/sh if mount | grep -q /mnt/usb; then echo `date +%R\ ` "usb device already mounted" else ...
4
votes
3answers
622 views

Escape sequences with “echo -e” in different shells

I just noticed that it seems like the flag -e does not exist for the echo command in my shell on Linux. Is this just a messed up setting or is it "normal"? Some code as an example: #!/bin/sh echo -e ...
4
votes
2answers
255 views

Quoted vs unquoted string expansion

for i in $(xrandr); do echo "$i" ; done for i in "$(xrandr)"; do echo "$i"; done for i in "$(xrandr)"; do echo $i; done I understand why 1 differs from 2. But why does 3 give a different output ...
1
vote
2answers
142 views

How to make sure the shell builtin echo is invoked so that its not visible in process list?

Is this going to be visible in the process listing if the below line is executed from a command line or a shell script bash -c "echo $password" or i just need to do echo $password from within ...
0
votes
2answers
92 views

Supress expansion of * in echo

I am working on a script which dynamically executes some queries on daily basis. These queries are coming from a table in the database. Here is the sample output of the query table: ...
-4
votes
2answers
607 views

Redirecting the content of a file to the command “echo”

I have a file named my_file.txt whose content is just the string Hello. How could I redirect its content to the command echo? I know I have the commands less, cat, more... but I need to do it with ...
4
votes
3answers
9k views

How do I set an environment variable on the command line and have it appear in commands?

If I run export TEST=foo echo $TEST It outputs foo. If I run TEST=foo echo $TEST It does not. How can I get this functionality without using export or a script?
2
votes
1answer
175 views

My echo command doesn't accept switches (echo -n or echo -e)

I have an echo statement in my script as below: echo -ne "Check Script"; I was expecting it to print Check Script but I am getting the below output -ne Check Script But when I run the same ...
3
votes
1answer
362 views

Printing colored text using script

When I type below command in the shell I get the OUTPUT in green color. Command echo "\033[32mCONNECTING TO abpwrk\033[m"; Output(in green color) CONNECTING TO abpwrk But if I use the same ...
22
votes
1answer
870 views

Why does echo >file use more real time than echo | sed >file?

The example, below, surprised me. It seems to be counter intuitive... aside from the fact that there is a whisker more user time for the echo | sed combo. Why is echo using so much sys time when it ...
6
votes
1answer
306 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 ...
4
votes
4answers
5k 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=` ...