|
1
|
#!/bin/sh -e
|
|
2
|
# Runs a stream command on a file
|
|
3
|
# Usage: [preserve_mtime=1] [preserve_mtime=1] self file command
|
|
4
|
|
|
5
|
file="$1"
|
|
6
|
shift
|
|
7
|
|
|
8
|
test "$#" -ge 1 || exit 0 # no command to run
|
|
9
|
|
|
10
|
temp="$(tempfile)"
|
|
11
|
onExit () { rm -f "$temp"; }
|
|
12
|
trap onExit EXIT
|
|
13
|
|
|
14
|
"$@" <"$file" >"$temp" # exits on error so file not updated
|
|
15
|
diff --brief "$file" "$temp" >/dev/null && exit # don't update file if no change
|
|
16
|
# --brief: avoid scanning the entire file for large files
|
|
17
|
if test "$preserve_mtime"; then touch -r "$file" "$temp"; fi
|
|
18
|
case "$(uname)" in Linux) chmod --reference="$file" "$temp";; esac
|
|
19
|
mv "$temp" "$file"
|
