Comment bash script?

Question

This is the portion of a bash script that is called from another script and by virtue of it's design uses this else statement.

How do I successfully add an echo or some other means to tell where it is not working? The script continues on to the next portion of the script but I have not idea how to tell if these commands ran.

I tried to add echo ""; after each command and it gives a 'not clean' error I assume b/c of the output.

else

  mysql -u dbrootadmin --password=`cat /root/.mysql_pw` << '_EOF_' >"$TMPFILE" 2>&1
FLUSH TABLES WITH READ LOCK;
FLUSH LOGS;
system  /usr/local/bin/CreateRootSnapshot
UNLOCK TABLES;
_EOF_

Everything after the line with `<< '_EOF_'` up to the line with `_EOF_` is fed to mysql, not processed by bash at all, so it would make sense that `echo`s in that area would have unexpected effects. — Charles Duffy, Jun 23 '17 at 19:42

score 1 · Accepted Answer · answered Jun 23 '17 at 17:43

1

You could turn on debugging and exiting if there is an error in bash. In the man-page under the "SHELL BUILTIN COMMANDS" section.

set -x makes the shell expand what it's doing and echo it out.

set -e makes the shell exit if there is an error.

answered Jun 23 '17 at 17:43

Timothy Brown

2,220
18
22

so in the first line do this? #!/bin/bash -x – Rocco The Taco Jun 23 '17 at 18:27
Yes. Or any other line `set -xe` (for example). – Timothy Brown Jun 23 '17 at 18:36
Is my syntax okay as I posted above or do I actually put 'set -xe' on it's own line? – Rocco The Taco Jun 23 '17 at 18:55
`set -e` is not good advice. See [BashFAQ #105](http://mywiki.wooledge.org/BashFAQ/105) (feel free to skip the allegory, and see if you can answer the questions below it about which behaviors the shell will have with `set -e` under which circumstances). – Charles Duffy Jun 23 '17 at 19:38
I don't plan on using -e but it sure would be nice is somebody could answer my question on placement. – Rocco The Taco Jun 23 '17 at 19:39
1

@RoccoTheTaco, you certainly *can* put it on its own line (preceded with `set`), or you can put it in the shebang (without). Either will work. – Charles Duffy Jun 23 '17 at 19:39
1

https://www.in-ulm.de/~mascheck/various/set-e/ is another reference discussing how the behavior of `set -e` differs across various shells. – Charles Duffy Jun 23 '17 at 20:00

Comment bash script?

1 Answers1