Bash: How to escape minus in `if [ … ` (alias “testâ€)?
Clash Royale CLAN TAG#URR8PPP
up vote
-1
down vote
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I need to test this:
kill -0 $LAST_PID;
So I wrote
if [ kill -0 $LAST_PID ] ; then ...
But this results in an error - unknown operator after - or so.
how do I escape the options within if?
scripting kill test
edited Aug 15 at 16:27
Jeff Schaller
32.6k849110
asked Aug 15 at 16:23
Ondra Žižka
467311
add a comment |Â
up vote
-1
down vote
favorite
I need to test this:
kill -0 $LAST_PID;
So I wrote
if [ kill -0 $LAST_PID ] ; then ...
But this results in an error - unknown operator after - or so.
how do I escape the options within if?
scripting kill test
edited Aug 15 at 16:27
Jeff Schaller
32.6k849110
asked Aug 15 at 16:23
Ondra Žižka
467311
1
Not sure why it's downvoted but since it is, it's probably a bad question and needs to be deleted.
– Ondra Žižka
Aug 15 at 23:44
add a comment |Â
up vote
-1
down vote
favorite
up vote
-1
down vote
favorite
I need to test this:
kill -0 $LAST_PID;
So I wrote
if [ kill -0 $LAST_PID ] ; then ...
But this results in an error - unknown operator after - or so.
how do I escape the options within if?
scripting kill test
edited Aug 15 at 16:27
Jeff Schaller
32.6k849110
asked Aug 15 at 16:23
Ondra Žižka
467311
I need to test this:
kill -0 $LAST_PID;
So I wrote
if [ kill -0 $LAST_PID ] ; then ...
But this results in an error - unknown operator after - or so.
how do I escape the options within if?
scripting kill test
scripting kill test
edited Aug 15 at 16:27
Jeff Schaller
32.6k849110
asked Aug 15 at 16:23
Ondra Žižka
467311
edited Aug 15 at 16:27
Jeff Schaller
32.6k849110
asked Aug 15 at 16:23
Ondra Žižka
467311
edited Aug 15 at 16:27
Jeff Schaller
32.6k849110
edited Aug 15 at 16:27
Jeff Schaller
32.6k849110
edited Aug 15 at 16:27
Jeff Schaller
32.6k849110
32.6k849110
asked Aug 15 at 16:23
Ondra Žižka
467311
asked Aug 15 at 16:23
Ondra Žižka
467311
asked Aug 15 at 16:23
Ondra Žižka
467311
467311
1
Not sure why it's downvoted but since it is, it's probably a bad question and needs to be deleted.
– Ondra Žižka
Aug 15 at 23:44
add a comment |Â
1
Not sure why it's downvoted but since it is, it's probably a bad question and needs to be deleted.
– Ondra Žižka
Aug 15 at 23:44
1
1
Not sure why it's downvoted but since it is, it's probably a bad question and needs to be deleted.
– Ondra Žižka
Aug 15 at 23:44
Not sure why it's downvoted but since it is, it's probably a bad question and needs to be deleted.
– Ondra Žižka
Aug 15 at 23:44
add a comment |Â
1 Answer
1
active
oldest
votes
up vote
4
down vote
accepted
It's not if that you're trying to escape it from, it's test / [. But you aren't testing the executing of kill that way; you're testing strings. You want:
if kill -0 "$LAST_PID"; then ...
that will test kill's return code.
answered Aug 15 at 16:27
Jeff Schaller
32.6k849110
add a comment |Â
1 Answer
1
active
oldest
votes
1 Answer
1
active
oldest
votes
active
oldest
votes
active
oldest
votes
up vote
4
down vote
accepted
It's not if that you're trying to escape it from, it's test / [. But you aren't testing the executing of kill that way; you're testing strings. You want:
if kill -0 "$LAST_PID"; then ...
that will test kill's return code.
answered Aug 15 at 16:27
Jeff Schaller
32.6k849110
add a comment |Â
up vote
4
down vote
accepted
It's not if that you're trying to escape it from, it's test / [. But you aren't testing the executing of kill that way; you're testing strings. You want:
if kill -0 "$LAST_PID"; then ...
that will test kill's return code.
answered Aug 15 at 16:27
Jeff Schaller
32.6k849110
add a comment |Â
up vote
4
down vote
accepted
up vote
4
down vote
accepted
It's not if that you're trying to escape it from, it's test / [. But you aren't testing the executing of kill that way; you're testing strings. You want:
if kill -0 "$LAST_PID"; then ...
that will test kill's return code.
answered Aug 15 at 16:27
Jeff Schaller
32.6k849110
It's not if that you're trying to escape it from, it's test / [. But you aren't testing the executing of kill that way; you're testing strings. You want:
if kill -0 "$LAST_PID"; then ...
that will test kill's return code.
answered Aug 15 at 16:27
Jeff Schaller
32.6k849110
answered Aug 15 at 16:27
Jeff Schaller
32.6k849110
answered Aug 15 at 16:27
Jeff Schaller
32.6k849110
answered Aug 15 at 16:27
Jeff Schaller
32.6k849110
32.6k849110
add a comment |Â
add a comment |Â
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1
Not sure why it's downvoted but since it is, it's probably a bad question and needs to be deleted.
– Ondra Žižka
Aug 15 at 23:44