I'm running the following command (on Ubuntu)
time wget 'http://localhost:8080/upLoading.jsp' --timeout=0
and get a result in the command line
real 0m0.042s
user 0m0.000s
sys 0m0.000s
I've tried the following:
time -a o.txt wget 'http://localhost:8080/upLoading.jsp' --timeout=0
and get the following error
-a: command not found
I want to get the result to be redirected to some file. How can I do that?
-a is only understood by the time binary (/usr/bin/time), When just using time you're using the bash built-in version which does not process the -a option, and hence tries to run it as a command.
/usr/bin/time -o foo.txt -a wget 'http://localhost:8080/upLoading.jsp' --timeout=0
Checking man time, I guess what you need is
time -o o.txt -a ...
(Note you need both -a and -o).
[EDIT:] If you are in bash, you must also take care to write
/usr/bin/time
(check manpage for explanation)
You can direct the stdout output of any commmand to a file using the > character.
To append the output to a file use >>
Note that unless done explicitly, output to stderr will still go to the console. To direct both stderr and stdout to the same output stream use
command 2>&1 outfile.txt (with bash)
or
command >& outfile.txt (with t/csh)
If you are working with bash All about redirection will give you more details and control about redirection.
\time 2> time.out.text command
\time -o time.out.text command
This answer based on earlier comments. It is tested it works. The advantage of the \ over /usr/bin/ is that you don't have to know the install directory of time.
These answers also only capture the time, not other output.
Exactly the time from GNU writes it's output to stderr and if you want to redirect it to file, you can use --output=PATH parameter of time
See this http://unixhelp.ed.ac.uk/CGI/man-cgi?time
And if you want to redirect stdout to some file, you can use > filename to create file and fill it or >> filename to append to some file after the initial command.
If you want to redirect stderr by yourself, you can use $ command >&2 your_stderr_output
Try to use /usr/bin/time since many shells have their own implementation of time which may or may not support the same flags as /usr/bin/time
so change your command to
/usr/bin/time -a -o foo.txt wget ....
How about your LANG ?
$ time -ao o.txt echo 1
bash: -ao: コマンドが見つかりません
real 0m0.001s
user 0m0.000s
sys 0m0.000s
$ export|grep LANG
declare -x LANG="ja_JP.utf8"
$ LANG=C time -ao o.txt echo 1
1
$ cat o.txt
0.00user 0.00system 0:00.00elapsed 0%CPU (0avgtext+0avgdata 1984maxresident)k
0inputs+0outputs (0major+158minor)pagefaults 0swaps
Try:
command 2> log.txt
and the real-time output from "command" can be seen in another console window with:
tail -f log.txt
This worked for me:
( time command ) |& tee output.txt
https://unix.stackexchange.com/questions/115980/how-can-i-redirect-time-output-and-command-output-to-the-same-pipe
You can do that with > if you want to redirect the output.
For example:
time wget 'http://localhost:8080/upLoading.jsp' --timeout=0 > output.txt 2>&1
2>&1 says to redirect STDERR to the same file.
This command will erase any output.txt files and creates a new one with your output. If you use >> it will append the output at the end of any existing output.txt file. If it doesn't exist, it will create it.
Related
I know this much:
$ command 2>> error
$ command 1>> output
Is there any way I can output the stderr to the error file and output stdout to the output file in the same line of bash?
Just add them in one line command 2>> error 1>> output
However, note that >> is for appending if the file already has data. Whereas, > will overwrite any existing data in the file.
So, command 2> error 1> output if you do not want to append.
Just for completion's sake, you can write 1> as just > since the default file descriptor is the output. so 1> and > is the same thing.
So, command 2> error 1> output becomes, command 2> error > output
Try this:
your_command 2>stderr.log 1>stdout.log
More information
The numerals 0 through 9 are file descriptors in bash.
0 stands for standard input, 1 stands for standard output, 2 stands for standard error. 3 through 9 are spare for any other temporary usage.
Any file descriptor can be redirected to a file or to another file descriptor using the operator >. You can instead use the operator >> to appends to a file instead of creating an empty one.
Usage:
file_descriptor > filename
file_descriptor > &file_descriptor
Please refer to Advanced Bash-Scripting Guide: Chapter 20. I/O Redirection.
Like that:
$ command >>output 2>>error
Or if you like to mix outputs (stdout & stderr) in one single file you may want to use:
command > merged-output.txt 2>&1
Multiple commands' output can be redirected. This works for either the command line or most usefully in a bash script. The -s directs the password prompt to the screen.
Hereblock cmds stdout/stderr are sent to seperate files and nothing to display.
sudo -s -u username <<'EOF' 2>err 1>out
ls; pwd;
EOF
Hereblock cmds stdout/stderr are sent to a single file and display.
sudo -s -u username <<'EOF' 2>&1 | tee out
ls; pwd;
EOF
Hereblock cmds stdout/stderr are sent to separate files and stdout to display.
sudo -s -u username <<'EOF' 2>err | tee out
ls; pwd;
EOF
Depending on who you are(whoami) and username a password may or may not be required.
I need to write the result of below command to a text file but this command doesn't work and when using cat output.txt show me nothing.
could please help me to correct the problem?
strace -r -y -e read Program -l -o output.txt
thanks
For future reference, I think the person should have ran it like this:
strace -o outputfile.txt ./Program
Using time ls, I have the following output:
$ time ls -l
total 2
-rwx------+ 1 FRIENDS None 97 Jun 23 08:59 location.txt
-rw-r--r--+ 1 FRIENDS None 10 Jun 23 09:06 welcome
real 0m0.040s
user 0m0.000s
sys 0m0.031s
Now, when I try to grep only the real value line, the actual result is:
$ time ls -l | grep real
real 0m0.040s
user 0m0.000s
sys 0m0.031s
My question is, how to get only the real value as output? In this case, 0m0.040s.
time writes its output to stderr, so you need to pipe stderr instead of stdout. But it's also important to remember that time is part of the syntax of bash, and it times an entire pipeline. Consequently, you need to wrap the pipeline in braces, or run it in a subshell:
$ { time ls -l >/dev/null; } 2>&1 | grep real
real 0m0.005s
With Bash v4.0 (probably universal on Linux distributions but still not standard on Mac OS X), you can use |& to pipe both stdout and stderr:
{ time ls -l >/dev/null; } |& grep real
Alternatively, you can use the time utility, which allows control of the output format. On my system, that utility is found in /usr/bin/time:
/usr/bin/time -f%e ls -l >/dev/null
man time for more details on the time utility.
(time ls -l) 2>&1 > /dev/null |grep real
This redirects stderr (which is where time sends its output) to the same stream as stdout, then redirects stdout to dev/null so the output of ls is not captured, then pipes what is now the output of time into the stdin of grep.
If you just want to specify the output format of time builtin, you can modify the value of TIMEFORMAT environment variable instead of filtering it with grep.
In you case,
TIMEFORMAT=%R
time ls -l
would give you the "real" time only.
Here's the link to relevant information in Bash manual (under "TIMEFORMAT").
This is a similar question on SO about parsing the output of time.
Look out.. bash has a built-in "time" command. Here are some of the differences..
# GNU time command (can also use $TIMEFORMAT variable instead of -f)
bash> /usr/bin/time -f%e ls >/dev/null
0.00
# BASH built-in time command (can also use $TIME variable instead of -f)
bash> time -f%e ls >/dev/null
-f%e: command not found
real 0m0.005s
user 0m0.004s
sys 0m0.000s
I think, it can be made a little easier:
time ls &> /dev/null | grep real
New to bash programming. I am not sure what is meant by 'output to stdout'. Does it mean print out to the command line?
If I have a simple bash script:
#!/bin/bash
wget -q http://192.168.0.1/test -O - | grep -m 1 'Hello'
it outputs a string to the terminal. Does this mean it's 'outputting to stdout' ?
Thanks
Yes, stdout is the terminal (unless it's redirected to a file using the > operator or into the stdin of another process using |)
In your specific example, you're actually redirecting using | grep ... through grep then to the terminal.
Every process on a Linux system (and most others) has at least 3 open file descriptors:
stdin (0)
stdout (1)
stderr (2)
Regualary every of this file descriptors will point to the terminal from where the process was started. Like this:
cat file.txt # all file descriptors are pointing to the terminal where you type the command
However, bash allows to modify this behaviour using input / output redirection:
cat < file.txt # will use file.txt as stdin
cat file.txt > output.txt # redirects stdout to a file (will not appear on terminal anymore)
cat file.txt 2> /dev/null # redirects stderr to /dev/null (will not appear on terminal anymore
The same is happening when you are using the pipe symbol like:
wget -q http://192.168.0.1/test -O - | grep -m 1 'Hello'
What is actually happening is that the stdout of the wget process (the process before the | ) is redirected to the stdin of the grep process. So wget's stdout isn't a terminal anymore while grep's output is the current terminal. If you want to redirect grep's output to a file for example, then use this:
wget -q http://192.168.0.1/test -O - | grep -m 1 'Hello' > output.txt
Unless redirected, standard output is the text terminal which initiated the program.
Here's a wikipedia article: http://en.wikipedia.org/wiki/Standard_streams#Standard_output_.28stdout.29
Let me present the scenario first with the command which is not working under linux bash environment.
$ timed-run prog1 1>/dev/null 2>out.tmp
Here in the above case I want to redirect the output of program 'prog1' to /dev/null and out.tmp file. But this command is redirecting the output (if any) of timed-run to out.tmp.
Any help will be appreciated.
From a simple example, I experience exactly the opposite.
$ time ls 1> foo 2> bar
real 0m0.002s
user 0m0.004s
sys 0m0.000s
$ more foo
<show files>
$ more bar
<empty>
$
The output of ls is redirected, and the output of time is not!
The problem here is in timed-run not in bash. If you run the same command replacing timed-run with the standard time command this works as you expect. Mainly timed run needs to run the arguments of prog1 through the shell again. If it is a shell script you can do this with the eval command. For example:
#!/bin/sh
echo here is some output
echo $*
eval $*
now run
timed-run prog1 '1>/dev/null' '2>output.tmp'
How about using sh -c 'cmd' like so:
time -p sh -c 'ls -l xcvb 1>/dev/null 2>out.tmp'
time -p sh -c 'exec 0</dev/null 1>/dev/null 2>out.tmp; ls -l xcvb'
# in out.tmp:
# ls: xcvb: No such file or directory