Inconsistent behavior of Bash

Asked Aug 10 '17 at 12:10

Active Dec 16 '18 at 04:07

Viewed 32 times

I have a file named "open". I open up a terminal, read it's first line into a variable text and tried to put all the contents of file except for text in a new file called "open.temp" using grep's pattern inversion. Here's the code:

papagolf@Sierra ~/My Files/My Programs % cat open
# PPPP
QQQQ
RRRR
SSSS
papagolf@Sierra ~/My Files/My Programs % text=`head -n 1 open`
papagolf@Sierra ~/My Files/My Programs % cat open | grep -v $text > open.temp
papagolf@Sierra ~/My Files/My Programs % cat open.temp 
QQQQ
RRRR
SSSS

But when I put the same commands in a file called "test.sh", give it executable permission and execute it, it pops an error.

papagolf@Sierra ~/My Files/My Programs % rm open.temp
papagolf@Sierra ~/My Files/My Programs % touch test.sh
papagolf@Sierra ~/My Files/My Programs % nano test.sh  
papagolf@Sierra ~/My Files/My Programs % chmod +x test.sh 
papagolf@Sierra ~/My Files/My Programs % ./test.sh 
grep: PPPP: No such file or directory
papagolf@Sierra ~/My Files/My Programs % cat test.sh 
text=`head -n 1 open`
cat open | grep -v $text > open.temp

edited Dec 16 '18 at 04:07

Rui F Ribeiro

55,929
26
146
227

asked Aug 10 '17 at 12:10

7_R3X

1,134
2
14
28

Why not replace the the second part of the operation by e.g. `sed 1d open >open.temp`? – Kusalananda Aug 10 '17 at 12:15
3

You are trying to execute `grep -v # PPPP`: search for "#" in the file "PPPP". Use quotation marks on `"$text"` so that you are grepping for `# PPPP` instead of `#` in `PPPP`. – user4556274 Aug 10 '17 at 12:18
@Kusalananda I've never used `sed` actually. :P But what's wrong with my method? It seems to work in the terminal, just not in the file. – 7_R3X Aug 10 '17 at 12:19
1

Double-quote your variables. – Kusalananda Aug 10 '17 at 12:20
1

@user4556274 : Yup! It worked. Thanks for the explanation. It's more important that the real answer. – 7_R3X Aug 10 '17 at 12:21
2

@Kusalananda, or just `tail -n +2 open > open.temp` – Stéphane Chazelas Aug 10 '17 at 12:22

Inconsistent behavior of Bash

0 Answers0