check #!/bin/sh-shebanged scripts in /usr/bin for dash-incompatible syntax using shellcheck.

bashism-check.sh

#!/bin/sh

# check #!/bin/sh-shebanged scripts in /usr/bin for
# dash-incompatible syntax using shellcheck.

# config
outdir=~/bashisms
searchdir=/usr/bin

mkdir -p "$outdir" || exit 1

for file in "$searchdir"/*; do
    [ -f "$file" ] && [ -r "$file" ] && sed -n '/^#!\/bin\/sh/q0;q1' "$file" || continue
    shchmsg=$(shellcheck -s dash -i 2039,2169,2240,2279,$(seq -s, 3001 3060) "$file")
    [ $? -eq 0 ] && continue
    basename=${file##*/}
    echo "$basename"
    printf '%s\n' "$shchmsg" > "$outdir/$basename"
done