Re: [PATCH v3 6/7] create/adjust generated/autoksyms.h

[Zev Weiss]

On Thu, Feb 18, 2016 at 15:07:02 -0500, Nicolas Pitre wrote:
> diff --git a/scripts/adjust_autoksyms.sh b/scripts/adjust_autoksyms.sh
> new file mode 100755
> index 0000000000..898a3ca1b2
> --- /dev/null
> +++ b/scripts/adjust_autoksyms.sh
> @@ -0,0 +1,97 @@
> +#!/bin/sh

Given the here-strings in this script, this should probably be /bin/bash 
or breakage will ensue on Debian and suchlike where /bin/sh != bash.  
However...

> +sed -ns -e '3s/ /\n/gp' "$MODVERDIR"/*.mod | sort -u |
> +while read sym; do
> +	if [ -n "$CONFIG_HAVE_UNDERSCORE_SYMBOL_PREFIX" ]; then
> +		sym=$(sed 's/^_//' <<< "$sym")

...this one could (shell-portably and more efficiently) be a parameter 
expansion (sym="${sym#_}").

> +
> +# Extract changes between old and new list and touch corresponding
> +# dependency files.
> +# Note: sort -m doesn't work well with underscore prefixed symbols so we
> +# use 'cat ... | sort' instead.
> +changed=0
> +while read sympath; do
> +	[ -z "$sympath" ] && continue
> +	depfile="include/config/ksym/${sympath}.h"
> +	mkdir -p "$(dirname "$depfile")"
> +	touch "$depfile"
> +	changed=$((changed + 1))
> +done <<< "$(
> +	cat "$cur_ksyms_file" "$new_ksyms_file" | sort | uniq -u |
> +	sed -n 's/^#define __KSYM_\(.*\) 1/\1/p' | tr "A-Z_" "a-z/"  )"

Nothing super-obvious springs to mind as a pure-sh equivalent for this 
one though, so assuming the script remains bash-specific, a process 
substitution like

 done < <(cat ...)

might slightly cleaner than the here-string + command substitution 
(doesn't need quoting, and just streams through a pipe rather than bash 
snarfing it all up into a string).