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The echo command writes text to standard output (stdout). The syntax of using the echo command is pretty straightforward: echo [OPTIONS] STRING... Some common usages of the echo command are piping shell variable to other commands, writing text to stdout in a shell script, and redirecting text to a file.
echo command in linux is used to display line of text/string that are passed as an argument . This is a built in command that is mostly used in shell scripts and batch files to output status text to the screen or a file. In above example, text after \c is not printed and omitted trailing new line.
If set, the return value of a pipeline is the value of the last (rightmost) command to exit with a non-zero status, or zero if all commands in the pipeline exit successfully. This option is disabled by default. Without pipefail , the return value of a pipeline is the exit status of the last command.
set -o xtrace
or
bash -x myscript.sh
This works with standard /bin/sh as well IIRC (it might be a POSIX thing then)
And remember, there is bashdb (bash Shell Debugger, release 4.0-0.4)
To revert to normal, exit the subshell or
set +o xtrace
The easiest way to do this is to let bash do it:
set -x
Or run it explicitly as bash -x myscript.
set -x is fine, but if you do something like:
set -x;
command;
set +x;
it would result in printing
+ command
+ set +x;
You can use a subshell to prevent that such as:
(set -x; command)
which would just print the command.
set -x is fine.
Another way to print each executed command is to use trap with DEBUG.
Put this line at the beginning of your script :
trap 'echo "# $BASH_COMMAND"' DEBUG
You can find a lot of other trap usages here.
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