Watch file for changes and run command
Content
Watch a file for file modifications and run a command. For known file extensions, the script may run itself. For all other extensions, specify a command to run.
Usage:
$ watch_file path/to/script.py
$ wf script.py "python script.py"
$ wf script.py
$ wf script.py "bash run.sh"
$ wf page.html "open https://www.example.com/"
watch_file ()
{
filename="${1}";
cmd="${2}";
cols=$(tput cols);
if [[ "${OSTYPE}" == "linux-gnu" ]]; then
python_script=$(cat <<'EOF'
import os
import pipes
import sys
filename = sys.argv[1]
_, file_extension = os.path.splitext(filename)
filepath = os.path.abspath(filename)
cmd = sys.argv[2]
if not cmd:
if file_extension == '.js':
cmd = 'node {0}'.format(pipes.quote(filename))
elif file_extension == '.php':
cmd = 'php {0}'.format(pipes.quote(filename))
elif file_extension == '.py':
cmd = 'python {0}'.format(pipes.quote(filename))
elif file_extension == '.sh':
cmd = 'bash {0}'.format(pipes.quote(filename))
print(cmd)
EOF
);
cmd=$(python -c "${python_script}" "${filename}" "${cmd}");
echo;
while inotifywait --event modify --quiet "${filename}"; do
printf -- '-=%.0s' $(eval echo {1.."${cols}"});
echo;
if [ ! -z "${cmd}" ]; then
bash -c "${cmd}";
fi;
done;
else
if [[ "${OSTYPE}" == "darwin"* ]]; then
echo -e '\x1b[0;93mWARNING\x1b[0m: watch using polling';
python_script=$(cat <<'EOF'
import math
import os
import pipes
import random
import shlex
import subprocess
import sys
import time
cols = int(sys.stdin.read().rstrip())
separator = '-=' * int(math.floor(cols / 2))
filename = sys.argv[1]
_, file_extension = os.path.splitext(filename)
filepath = os.path.abspath(filename)
cmd = sys.argv[2]
if not cmd:
if file_extension == '.js':
cmd = 'node {0}'.format(pipes.quote(filename))
elif file_extension == '.php':
cmd = 'php {0}'.format(pipes.quote(filename))
elif file_extension == '.py':
cmd = 'python {0}'.format(pipes.quote(filename))
elif file_extension == '.sh':
cmd = 'bash {0}'.format(pipes.quote(filename))
cmd_parts = shlex.split(cmd)
print(cmd)
last = cur = os.path.getmtime(filepath)
while True:
time.sleep(1)
try:
cur = os.path.getmtime(filepath)
if cur != last:
last = cur
print(separator)
proc = subprocess.Popen(cmd_parts)
proc.communicate()[0]
print('return code: %s' % proc.returncode)
print
time.sleep(1)
print(random.random())
except OSError as e:
print('failed to get file modification time (%s)' % e.message)
EOF
);
echo "${cols}" | python -c "${python_script}" "${filename}" "${cmd}";
fi;
fi
}
alias wf="watch_file"
Part of https://github.com/dot-star/dot-star
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See also https://www.darklaunch.com/watch-files-and-run-a-command