Shell script debugging

rbautch · 07-19-2006, 06:56 PM

I'd like to add some echo statements throughout my script for dubugging purposes, but I'd like to be able so suppress them with a command line argument. I don't want the full -x dubug, just the echoes. My initial thought was to replace all the echoes with a function that gets defined using a command line argument. Is there a more elegant way?

Matir · 07-19-2006, 07:16 PM

I'm a big fan of:

Code:

[ $DBG_MODE ] && echo "Debug message"

DBG_MODE=1 ./script

jlinkels · 07-20-2006, 06:23 AM

This is my standard way:

Code:

debug_out=/dev/stderr
#debug_out=/dev/null

...

echo "my debug statement" > $debug_out

This way I can have my debug statements in the console, to null, or to a file at will.

jlinkels

Emmanuel_uk · 07-20-2006, 06:37 AM

set -o verbose
# Echoes all commands before executing
set +o verbose

is also handy

konsolebox · 07-20-2006, 08:42 AM

this is the thing i always do when making script files:

Code:

message() {
   [ "$MESSAGE" ] && echo "$@"
}

debug() {
   [ "$DEBUG" ] && echo "$@"
}

error() {
   [ "$ERROR" ] && echo "$@"
}

warning() {
   [ "$WARNING" ] && echo "$@"
}

MESSAGE=1
message "your message" "anything"

DEBUG=1
debug "any"

ERROR=1
error "any"

WARNING=1
warning "any"

bigearsbilly · 07-20-2006, 08:51 AM

Code:

alias BUG=echo  # turn it on
alias BUG=:     # turn it off
# then:
BUG hello there

edit:
or alias DEBUG=\#

konsolebox · 07-20-2006, 09:18 AM

darn. for almost a year of exploring bash i never thought of that kind of code. wow you saved me a lot of statements. thanks a lot billy.

bigearsbilly · 07-20-2006, 09:21 AM

Simple is cool!

I've been at this game for a LONG time.
still learning though

konsolebox · 07-20-2006, 09:37 AM

oh i forgot. the reason i wasn't using alias is because alias won't accept parameters. example alias DEBUG="2>&1 echo anything". and practically it's more easier to modify a function than an alias. so when you do:

Code:

message() {
   echo "$@" #this is for stdout
   #but what if i'll add for the logfile
   echo "$@" >> debug.log
}

anyway it depends on the usage.
aliases are simpler. functions are more flexible.
at least we have choices hehehe
thanks again billy for the info

Matir · 07-20-2006, 09:52 AM

That is actually a really cool trick. I'd probably add >/dev/stderr on the end, but that's just me.

rbautch · 07-20-2006, 10:30 PM

Wow, thanks for all the great responses guys. I'll give a few of these a try.

Matir · 07-20-2006, 10:33 PM

No problem. Let us know which one you find works best for you!