Question: Currently I have my bash script using `exec 22>&2 21>&1 1>$log 2>&1` to write stderr and stdout to a log file. I would like to add a time stamp for each entry, but I haven't found an easy way to do that. Ideally it would be a simple change to the current command with the time being written on the same line before the rest.

Here's a script that I'm using the command in:

```
#!/bin/bash

#This script takes the server to rysnc as an argument. You can also tell 
#the script to check the server_status.txt file.
#
#Example: /path/to/script/sync.sh grail true
#
#The arguments are order senstive. The server name must come before the status
#check value.

#Logfile
LOG=/var/log/sync.log

DIRECTORYS="auth/ keys/ log/mailwhen/ intranet/ www/calmaa/data/ www/admatch/data/ www/sfhsa/data/ www/hfa3_org www/padmatch/ www/serverdown/"

if [ "x$2" == "xfalse" ]; then
    return 0
elif [ "x$2" == "xtrue" ]; then
    if [ `cat /srv/www/wan*/server_status.txt` == "primary" ]; then
        exit 0
    fi
else
    echo "Please use \"true\" or \"false\" for the second value." 
    exit 1
fi

# Copy stdout and stderr, and then open the logfile
exec 22>&2 21>&1 1>$log 2>&1
# Here is how to restore stdout and stderr:
# exec 2>&22 1>&21

for DIRECTORY in $DIRECTORYS; do
    rsync -azu --delete --bwlimit=500 $1:/srv/$DIRECTORY  /srv/$DIRECTORY
done

```

Answer: 
Without seeing more of your script I can't tell you the best way for your particular needs. However this is a general way that can be adapted for your needs.

```
exec > >(while read -r line; do printf '%s %s\n' "$(date --rfc-3339=seconds)" "$line"; done)

```

Each line of text that is output will have the timestamp for the time that it occurred prepended. The output will look something like this:

```
2013-09-04 21:32:14-05:00 An event occurred and this is the message
2013-09-04 21:32:37-05:00 Some time passed, another event produced a message

```
edit stream with `sed`:

```
sed "s/^/$(date -u) /"

```

using pipe:

```
[root@giomacdesk ~]# cat test.txt 
asd1
asd2
[root@giomacdesk ~]# cat test.txt |sed "s/^/$(date -u) /"
ოთხ სექ  4 19:00:53 UTC 2013 asd1
ოთხ სექ  4 19:00:53 UTC 2013 asd2
[root@giomacdesk ~]# 

```