implemented patchfile and pre post action of package manager, renamed pkgrem -> pkgrm

lib/filefct.sh

@@ -177,9 +177,39 @@ isdirempty()
 
 # ------------------------------------------------------------------------------
 # patch a file replacing all @var@ by the corresponding value in environment
+# or the variable list given in parameter
 patchfile()
 {
-    : # todo
+    local dstfile=$1 && shift
+    local workfile=${dstfile}.work
+
+    # Create a sub-process, to avoid bash environment pollution
+    (
+        local varlist= pattern=
+        if [[ $# -eq 0 ]] ; then
+            pattern="-e s/<\(.*\)>/\$\1\$\1/g"
+        else
+            local var=
+            for var in $* ; do
+                if ! declare -p $var >/dev/null 2>&1 ; then
+                    local $var=$(eval echo \$$var)
+                fi
+                export $var
+                pattern="$pattern -e s/@$var@/\$$var/g"
+                varlist=$varlist\$$var
+            done
+        fi
+
+        # sed replace <VAR> with \$$VAR and envsubst do the replace by value
+        sed $pattern $dstfile | envsubst ${varlist:+"$varlist"} > "$workfile"
+    )
+
+    local -a rights=( $(stat --printf="%a %u %g" "$dstfile") )
+    mv "$workfile" "$dstfile"
+    chmod ${rights[0]} "$dstfile"
+    chown ${rights[1]}:${rights[2]} "$dstfile"
+
+    unset dstfile
 }
 
 # EOF