A shell script to update 'isFixedPitch' attribute 'value' from 0 to 1 on OpenType POST table. Also updates the font version.

set-is_fixed_pitch-to_true.sh

# requires XMLstarlet: https://brewformulas.org/Xmlstarlet
# requires gftools: pip install git+https://github.com/googlefonts/gftools

# updates isFixedPitch attribute 'value' from 0 to 1 on OpenType POST table
#
# USAGE:
# TTX a file in the family to see its current version number in nameID 5
# $ ttx -t name <font_path>
# then, on the command line, run:
# $ chmod +x <relative_path>/set-is_fixed_pitch.sh
# $ ./set-is_fixed_pitch.sh <font_directory_path> <old_version> <new_version>

set -e

directory=$1
oldVersion=$2
newVersion=$3
cd $directory

# clean up any existing ttx files
for file in ./*; do
    if [[ $file == *".ttx" ]]; then
        rm $file
    fi
done

# TTX; set isFixedPitch to 1; update HEAD 
ttfs=$(ls ./*.ttf)
for ttf in $ttfs; do
    ttx $ttf
    rm $ttf
    ttxPath=${ttf/".ttf"/".ttx"}
    # this edits, in the same file, the isFixedPitch attribute 'value' to 1
    xml ed --inplace -u "/*/post/isFixedPitch[@value=0]/@value" -v 1 $ttxPath
    # this edits, in the same file, the head version value to newVersion
    xml ed --inplace -u "/*/head/fontRevision[@value=$oldVersion]/@value" -v $newVersion $ttxPath
    ttx $ttxPath
    rm $ttxPath
done

# # use gftools to bump version number of fonts
gftools update-version $ttfs $oldVersion $newVersion

# if there are fixed files, remove old ttfs and move fixed into their place
for file in ./*; do
    if [[ $file == *".fix" ]]; then
        rm ${file/".ttf.fix"/".ttf"}
        cp $file ${file/"ttf.fix"/"ttf"}
        rm $file
    fi
done

# TTX new files and print updates to terminal to confirm results
ttfs=$(ls ./*.ttf)
for ttf in $ttfs; do
    echo =================================================
    echo $(basename $file)
    ttx -t name -t head -t post -q $ttf
    ttxPath=${ttf/".ttf"/".ttx"}
    # print font nameID 5 (version)
    echo NAME nameID 5:
    versionName=$(xml sel --noblanks --indent --text -t -v "*/name/namerecord[@nameID=5]" $ttxPath)
    echo → ${versionName/"\n"/""}
    # print head fontRevision value
    echo HEAD fontRevision:
    fontRevision=$(xml sel --noblanks --indent --text -t -v "*/head/fontRevision[@value]/@value" $ttxPath)
    echo → ${fontRevision/"\n"/""}
    # print post table isFixedPitch
    echo POST isFixedPitch:
    isFixedPitch=$(xml sel --noblanks --indent --text -t -v "*/post/isFixedPitch[@value]/@value" $ttxPath)
    echo → ${isFixedPitch/"\n"/""}

    rm $ttxPath
done