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Make explanation on how to fix this check on sh clearer, add example of heredoc

Alejandro González
2022-04-13 21:47:22 +02:00
parent de8c265789
commit 8ef0dc0dcc
1 changed files with 9 additions and 1 deletions
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10
SC2031.md

@@ -18,7 +18,15 @@ n=0
while read i; do (( n+=i )); done < <(printf "%s\n" {1..10})
echo $n
```
In `sh`, a temp file (better if fifo or fd) can be used instead of process substitution. And if it's acceptable to do it with waiting, try Here Documents.
In `sh`, temporary files, FIFOs or file descriptors can be used instead. When the output of the command can be stored to a variable before entering the loop, here documents are a preferable alternative:
```sh
n=0
SUMMANDS="$(printf '%s\n%s\n%s\n%s\n%s\n%s\n%s\n%s\n%s\n%s\n' 1 2 3 4 5 6 7 8 9 10)"
while read i; do n=$(( n + i )); done <<SUMMANDS_INPUT
$SUMMANDS
SUMMANDS_INPUT
echo $n
```
With Bash 4.2+ you can also use `shopt -s lastpipe` which will change the pipe behaviour to be similar to Ksh and Zsh (see Rationale below) [as long as job control is not active](https://www.gnu.org/software/bash/manual/html_node/The-Shopt-Builtin.html) (e.g. inside a script):