add tip about epm repo --help and improve epm repo --help

bin/epm-filelist

@@ -29,7 +29,7 @@ __alt_local_content_filelist()
     load_helper epm-sh-altlinux
 
     local CI="$(get_local_alt_contents_index)"
-    [ -n "$CI" ] || fatal "Have no local contents index"
+    [ -n "$CI" ] || fatal "Have no local contents index. Check epm repo --help."
 
     # TODO: safe way to use less
     #local OUTCMD="less"

bin/epm-repo

@@ -27,6 +27,13 @@ epm_repo()
 	case $CMD in
 	"-h"|"--help"|help)               # HELPCMD: help
 		get_help HELPCMD $SHAREDIR/epm-repo
+cat <<EOF
+Examples:
+  epm repo set p9
+  epm repo add autoimports
+  epm repo list
+  epm repo change yandex
+EOF
 		;;
 	""|list)                          # HELPCMD: list packages
 		load_helper epm-repolist

bin/epm-search_file

@@ -34,7 +34,7 @@ __alt_local_content_search()
     info "Locate contents index file(s) ..."
     local CI="$(get_local_alt_contents_index)"
     # TODO use something like
-    [ -n "$CI" ] || fatal "Have no local contents index"
+    [ -n "$CI" ] || fatal "Have no local contents index. Check epm repo --help."
 
     info "Searching in"
     echo "$CI"