Grep behaves diffrent upon printf or echo output

Shell Programming and Scripting
1

Hello

I want to check whether certain arguments were passed to the script, and when those are, not doing a log entry.
If those arguments are not passed, always do a log entry (new call).

What currently i have is this:

	echo "${@}"|grep -q \\-[Lih] || \
		tui-log -e "$LOG" "\r---- New call $$ ----"

Which upon these 2 commands, produces these lines within the logfiles:

vhs -h ; vhs -L

With echo i have the expected output:

21:42:46         Show Help
21:42:46         Show Logfile
21:42:49         Show Help
21:42:49         Show Logfile

However, as soon i change echo to become printf , it produces this (not wanted):

---- New call 17388 ----
21:44:19         Show Help

---- New call 17423 ----
21:44:19         Show Logfile

In addition i wanted to use [[:space:]]\\-[Lih] , but i assume that is another issue?
I've tried quoting the regex, but still fails.

System:

export LC_ALL=C ; uname -r ; echo "--" ; $SHELL --version
3.16.3-200.fc20.x86_64
--
GNU bash, version 4.2.51(1)-release (x86_64-redhat-linux-gnu)
Copyright (C) 2011 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>

This is free software; you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.

Any ideas?
Thank you in advance

2

You only care if 1 of those 3 options are passed? And how did you use printf?

$ echo "$@"
one two three
$ printf "$@"
one$

Clearly the printf statement needs to be different. This will give the same string:

$ printf '%s\n' "$*"
one two three

But keeping the idea of using printf and grep, perhaps you want:

$ echo "$@"
-L -i
$ printf '%s\n' "$@" | grep -c -- -[Lih]
2

Now we know we had 2 of the 3 options...

1 Like
3

Although the filenames -L -i , and -h are not common, scripts should always assume that they might be present. Therefore, the grep -[Lih] operand should be quoted:

$ printf '%s\n' "$@" | grep -c -- '-[Lih]'
1 Like
4

Thanks Don (and Neutron too), that thought was actualy in mind, but only as part of a filename.
That just solved my 2nd question, i still was fiddling around, me used the wrong quotes :slight_smile:

EDIT:
Weird, the solved tag didnt put a [solved] prior to the threads title..

5

You can search on tags like solved, but they don't change the title of your thread. The solved tag is special in that it also has the side-effect of changing the color used when displaying the title of the thread from black to blue.

1 Like