Echo multiline var to Grep

Question

How do you pipe a multiline variable to grep and retain the newlines?

Expected results:

$ git status --porcelain --branch
## test-branch
M  image.go
 M item.go
?? addme.go
?? testdata/
$ git status --porcelain --branch | grep -c '^??'
2

"2" is the answer.

But in a script (or just entering the commands), I am not able to parse this $x from below.

$ x="$(git status --porcelain --branch)"
$ y="$(echo $x | grep -c '^??')"
$ echo "$y"
0

I suspect it is with how I am echoing $(echo $x ... within the y variable assignment.

EDIT: I am only executing x="$(git status --porcelain --branch)" one time, and parsing it a few dozen times with multiple grep commands for various outputs, values, counts, status, branches, behinds, aheads and other values. Therefore I need to assign the output of git status ... to a variable, and parse it multiple times.

PesaThe · Accepted Answer · 2017-12-10T23:56:32.913

13

If you don't quote $x, it will undergo word-splitting and echo will print one long line. You just need to use "$x":

x=$(git status --porcelain --branch)
y=$(echo "$x" | grep -c '^??')
echo "$y"

Also, you don't have to use extra echo:

y=$(grep -c '^??' <<< "$x")

I recommend using shellcheck. It is really helpful in such cases.

edited Dec 10 '17 at 23:56

answered Dec 10 '17 at 23:29

PesaThe

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I'll edit my question. I only want to run `git status ...` one time in a variable, and parse it a few dozen times over and over for various outputs, values, counts, status, branches, behinds, aheads, etc... – eduncan911 Dec 10 '17 at 23:31
1

@eduncan911 Oh, ok. I have update my answer accordingly. – PesaThe Dec 10 '17 at 23:34
Ah, yep. that did it! ha, i didn't have to quote the whole thing. – eduncan911 Dec 10 '17 at 23:35
1

@eduncan911 Exactly. When assigning to a variable, there is no word-splitting taking place. – PesaThe Dec 10 '17 at 23:36
Echo's are still warranted for multiple pipes: `$(echo "$x" | grep '^##' | grep -o '\[.\+\]$')` – eduncan911 Dec 10 '17 at 23:42
1

@eduncan911 `$(grep '^##' <<< "$x" | grep -o '\[.\+\]$')` – PesaThe Dec 10 '17 at 23:43

Echo multiline var to Grep

1 Answers1