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| -rw-r--r-- | functions/experimental.sh | 53 |
1 files changed, 53 insertions, 0 deletions
diff --git a/functions/experimental.sh b/functions/experimental.sh new file mode 100644 index 0000000..f577fa7 --- /dev/null +++ b/functions/experimental.sh @@ -0,0 +1,53 @@ +# Copyright 2024 Gentoo Authors +# Distributed under the terms of the GNU General Public License v2 +# shellcheck shell=sh disable=3043 + +# This file contains functions considered experimental in nature. Any functions +# defined here may eventually be promoted to the core library or to a distinct +# module. They may also be dropped without warning, either because they were +# not considered as being sufficiently within the scope of gentoo-functions as +# a project or because they were deemed to be insufficiently useful. As such, it +# serves as a staging ground for new ideas. Note that GENFUN_API_LEVEL must +# never be incremented on account of any changes made to this module. + +warn "sourcing the experimental module from gentoo-functions; no stability guarantee is provided" + +# +# Returns 0 provided that two conditions hold. Firstly, that the standard input +# is connected to a tty. Secondly, that the standard output has not been closed. +# This technique is loosely based on the IO::Interactive::Tiny module from CPAN. +# +is_interactive() +{ + test -t 0 && { true 3>&1; } 2>/dev/null +} + +# +# Continuously reads lines from the standard input, prepending each with a +# timestamp before printing to the standard output. Timestamps shall be in the +# format of "%FT%T%z", per strftime(3). Output buffering shall not be employed. +# +prepend_ts() +{ + if hash gawk 2>/dev/null; then + prepend_ts() + { + gawk '{ print strftime("%FT%T%z"), $0; fflush(); }' + } + elif hash ts 2>/dev/null; then + prepend_ts() + { + ts '%FT%T%z' + } + elif bash -c '(( BASH_VERSINFO >= 4 ))' 2>/dev/null; then + prepend_ts() + { + bash -c 'while read -r; do printf "%(%FT%T%z)T %s\n" -1 "${REPLY}"; done' + } + else + warn "prepend_ts: this function requires that either bash, gawk or moreutils be installed" + return 1 + fi + + prepend_ts +} |