How do I get both STDOUT and STDERR to go to the terminal and a log file?

Question

I have a script which will be run interactively by non-technical users. The script writes status updates to STDOUT so that the user can be sure that the script is running OK.

I want both STDOUT and STDERR redirected to the terminal (so that the user can see that the script is working as well as see if there was a problem). I also want both streams redirected to a log file.

I've seen a bunch of solutions on the net. Some don't work and others are horribly complicated. I've developed a workable solution (which I'll enter as an answer), but it's kludgy.

The perfect solution would be a single line of code that could be incorporated into the beginning of any script that sends both streams to both the terminal and a log file.

EDIT: Redirecting STDERR to STDOUT and piping the result to tee works, but it depends on the users remembering to redirect and pipe the output. I want the logging to be fool-proof and automatic (which is why I'd like to be able to embed the solution into the script itself.)

Answer 1

Update: Combining all my answers into one

Use "tee" to redirect to a file and the screen. Depending on the shell you use, you first have to redirect stderr to stdout using

./a.out 2>&1 | tee output

or

./a.out |& tee output

In csh, there is a built-in command called "script" that will capture everything that goes to the screen to a file. You start it by typing "script", then doing whatever it is you want to capture, then hit control-D to close the script file. I don't know of an equivalent for sh/bash/ksh.

Also, since you have no indicated that these are your own sh scripts that you can modify, you can do the redirection internally by surrounding the whole script with braces or brackets, like

  #!/bin/sh
  {
    ... whatever you had in your script before
  } 2>&1 | tee output.file

Answer 2

Use the tee program and dup stderr to stdout.

 program 2>&1 | tee > logfile

Answer 3

I created a script called "RunScript.sh". The contents of this script is:

${APP_HOME}/${1}.sh ${2} ${3} ${4} ${5} ${6} 2>&1 | tee -a ${APP_HOME}/${1}.log

I call it like this:

./RunScript.sh ScriptToRun Param1 Param2 Param3 ...

This works, but it requires the application's scripts to be run via an external script. It's a bit kludgy.

Answer 4

Another solution in csh (I don't know of an equivalent for sh/bash/ksh) is "script". Type "script", run your program, then close the script file using control-D.

Answer 5

the to redirect stderr to stdout append this at your command: 2>&1 For outputting to terminal and logging into file you should use tee

Both together would look like this:

 mycommand 2>&1 | tee mylogfile.log

EDIT: For embedding into your script you would do the same. So your script

#!/bin/sh
whatever1
whatever2
...
whatever3

would end up as

#!/bin/sh
( whatever1
whatever2
...
whatever3 ) 2>&1 | tee mylogfile.log

Answer 6

If these scripts are your own, and they're bash scripts, you can surround the whole guts of it with

  {
    your script
  } 2>&1 | tee foo

Answer 7

Use the script command in your script (man 1 script)

Create a wrapper shellscript (2 lines) that sets up script() and then calls exit.

Part 1: wrap.sh

#!/bin/sh
script -c './realscript.sh'
exit

Part 2: realscript.sh

#!/bin/sh
echo 'Output'

Result:

~: sh wrap.sh 
Script started, file is typescript
Output
Script done, file is typescript
~: cat typescript 
Script started on fr. 12. des. 2008 kl. 18.07 +0100
Output

Script done on fr. 12. des. 2008 kl. 18.07 +0100
~:

Answer 8

A year later, here's an old bash script for logging anything. For example,
teelog make ... logs to a generated log name (and see the trick for logging nested makes too.)

#!/bin/bash
me=teelog
Version="2008-10-9 oct denis-bz"

Help() {
cat <<!

    $me anycommand args ...

logs the output of "anycommand ..." as well as displaying it on the screen,
by running
    anycommand args ... 2>&1 | tee `day`-command-args.log

That is, stdout and stderr go to both the screen, and to a log file.
(The Unix "tee" command is named after "T" pipe fittings, 1 in -> 2 out;
see http://en.wikipedia.org/wiki/Tee_(command) ).

The default log file name is made up from "command" and all the "args":
    $me cmd -opt dir/file  logs to `day`-cmd--opt-file.log .
To log to xx.log instead, either export log=xx.log or
    $me log=xx.log cmd ...
If "logdir" is set, logs are put in that directory, which must exist.
An old xx.log is moved to /tmp/\$USER-xx.log .

The log file has a header like
    # from: command args ...
    # run: date pwd etc.
to show what was run; see "From" in this file.

Called as "Log" (ln -s $me Log), Log anycommand ... logs to a file:
    command args ... > `day`-command-args.log
and tees stderr to both the log file and the terminal -- bash only.

Some commands that prompt for input from the console, such as a password,
don't prompt if they "| tee"; you can only type ahead, carefully.

To log all "make" s, including nested ones like
    cd dir1; \$(MAKE)
    cd dir2; \$(MAKE)
    ...
export MAKE="$me make"

!
  # See also: output logging in screen(1).
    exit 1
}


#-------------------------------------------------------------------------------
# bzutil.sh  denisbz may2008 --

day() {  # 30mar, 3mar
    /bin/date +%e%h  |  tr '[A-Z]' '[a-z]'  |  tr -d ' '
}

edate() {  # 19 May 2008 15:56
    echo `/bin/date "+%e %h %Y %H:%M"`
}

From() {  # header  # from: $*  # run: date pwd ...
    case `uname` in Darwin )
     mac=" mac `sw_vers -productVersion`"
    esac
    cut -c -200 <<!
${comment-#} from: $@
${comment-#} run: `edate`  in $PWD `uname -n` $mac `arch` 

!
    # mac $PWD is pwd -L not -P real
}

    # log name: day-args*.log, change this if you like --
logfilename() {
    log=`day`
    [[ $1 == "sudo" ]]  &&  shift
    for arg
    do
     log="$log-${arg##*/}"  # basename
     (( ${#log} >= 100 ))  &&  break  # max len 100
    done
      # no blanks etc in logfilename please, tr them to "-"
    echo $logdir/` echo "$log".log  |  tr -C '.:+=[:alnum:]_\n' - `
}

#-------------------------------------------------------------------------------
case "$1" in
-v* | --v* )
    echo "$0 version: $Version"
    exit 1 ;;
"" | -* )
    Help
esac

    # scan log= etc --
while [[ $1 == [a-zA-Z_]*=* ]]; do
    export "$1"
    shift
done

: ${logdir=.}
[[ -w $logdir ]] || {
    echo >&2 "error: $me: can't write in logdir $logdir"
    exit 1
    }
: ${log=` logfilename "$@" `}
[[ -f $log ]]  &&
    /bin/mv "$log" "/tmp/$USER-${log##*/}"


case ${0##*/} in  # basename
log | Log )  # both to log, stderr to caller's stderr too --
{
    From "$@"
    "$@"
} > $log  2> >(tee /dev/stderr)  # bash only
    # see http://wooledge.org:8000/BashFAQ 47, stderr to a pipe
;;

* )
#-------------------------------------------------------------------------------
{
    From "$@"  # header: from ... date pwd etc.

    "$@"  2>&1  # run the cmd with stderr and stdout both to the log

} | tee $log
    # mac tee buffers stdout ?

esac