From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on inbox.vuxu.org X-Spam-Level: X-Spam-Status: No, score=-0.8 required=5.0 tests=DKIM_INVALID,DKIM_SIGNED, MAILING_LIST_MULTI,RCVD_IN_DNSWL_NONE autolearn=ham autolearn_force=no version=3.4.2 Received: from minnie.tuhs.org (minnie.tuhs.org [45.79.103.53]) by inbox.vuxu.org (OpenSMTPD) with ESMTP id 9cb49b3a for ; Sun, 19 Jan 2020 21:23:00 +0000 (UTC) Received: by minnie.tuhs.org (Postfix, from userid 112) id 0B0A59C154; Mon, 20 Jan 2020 07:22:59 +1000 (AEST) Received: from minnie.tuhs.org (localhost [127.0.0.1]) by minnie.tuhs.org (Postfix) with ESMTP id 2635A9C10B; Mon, 20 Jan 2020 07:22:32 +1000 (AEST) Authentication-Results: minnie.tuhs.org; dkim=fail reason="signature verification failed" (1024-bit key; secure) header.d=tnetconsulting.net header.i=@tnetconsulting.net header.b="I/uB+ZYP"; dkim-atps=neutral Received: by minnie.tuhs.org (Postfix, from userid 112) id 2D2249C10B; Mon, 20 Jan 2020 07:22:30 +1000 (AEST) Received: from tncsrv06.tnetconsulting.net (tncsrv06.tnetconsulting.net [45.33.28.24]) by minnie.tuhs.org (Postfix) with ESMTPS id 871AA9C0FD for ; Mon, 20 Jan 2020 07:22:29 +1000 (AEST) Received: from Contact-TNet-Consulting-Abuse-for-assistance by tncsrv06.tnetconsulting.net (8.15.2/8.15.2/Debian-3) with ESMTPSA id 00JLMRsj011465 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128 verify=NO) for ; Sun, 19 Jan 2020 15:22:28 -0600 DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=tnetconsulting.net; s=2019; t=1579468948; bh=iwMsxb5Blh5wX4lMehmk4unqwdOaFw/P1ZTNZI7RdWQ=; h=To:From:Subject:Message-ID:Date:User-Agent:MIME-Version: Content-Type:Cc:Content-Disposition:Content-Language: Content-Transfer-Encoding:Content-Type:Date:From:In-Reply-To: Message-ID:MIME-Version:References:Reply-To:Resent-Date: Resent-From:Resent-To:Resent-Cc:Sender:Subject:To:User-Agent; b=I/uB+ZYPrTYwXAUtju87hOsA5/Gdg+pQIp1STwIUSZzTPZtyVpuNDEK7UTncKOhmq DhdQ07FY8g0k7UYRgNkG2uaOHZ9H6X1hB0d+B+YgUBM+XEUJ0LK3uLZB+oaC/eaW9w ITR+csytjvHeLn9wOzc7uf4fPQCJD7Tpm5hO2GFg= To: The Unix Heritage Society Organization: TNet Consulting Message-ID: Date: Sun, 19 Jan 2020 14:22:29 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.2.2 MIME-Version: 1.0 Content-Type: multipart/signed; protocol="application/pkcs7-signature"; micalg=sha-256; boundary="------------ms050406080705040508040807" Subject: [TUHS] Shell Level... X-BeenThere: tuhs@minnie.tuhs.org X-Mailman-Version: 2.1.26 Precedence: list List-Id: The Unix Heritage Society mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , From: Grant Taylor via TUHS Reply-To: Grant Taylor Errors-To: tuhs-bounces@minnie.tuhs.org Sender: "TUHS" This is a cryptographically signed message in MIME format. --------------ms050406080705040508040807 Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: quoted-printable Hi, Have you ever used shell level, $SHLVL, in your weekly ~> daily use of Un= ix? I had largely dismissed it until a recent conversation in a newsgroup.=20 I learned that shelling out of programs also increments the shell level. = I.e. :shell or :!/bin/sh in vim. Someone also mentioned quickly starting a new sub-shell from the current = shell for quick transient tasks, i.e. dc / bc, mount / cp / unmount,=20 {,r,s}cp, etc., in an existing terminal window to avoid cluttering that=20 first terminals history with the transient commands. That got me to wondering if there were other uses for shell level=20 ($SHLVL). Hence my question. This is more about using (contemporary) shells on Unix, than it is about = Unix history. But I suspect that TUHS is one of the best places to find = the most people that are likely to know about shell level. Feel free to = reply to COFF if it would be better there. --=20 Grant. . . . unix || die --------------ms050406080705040508040807 Content-Type: application/pkcs7-signature; name="smime.p7s" Content-Transfer-Encoding: base64 Content-Disposition: attachment; filename="smime.p7s" Content-Description: S/MIME Cryptographic Signature MIAGCSqGSIb3DQEHAqCAMIACAQExDzANBglghkgBZQMEAgEFADCABgkqhkiG9w0BBwEAAKCC CzkwggUhMIIECaADAgECAhA53zcXtFD9dENby64EqrKqMA0GCSqGSIb3DQEBCwUAMIGWMQsw CQYDVQQGEwJHQjEbMBkGA1UECBMSR3JlYXRlciBNYW5jaGVzdGVyMRAwDgYDVQQHEwdTYWxm b3JkMRgwFgYDVQQKEw9TZWN0aWdvIExpbWl0ZWQxPjA8BgNVBAMTNVNlY3RpZ28gUlNBIENs aWVudCBBdXRoZW50aWNhdGlvbiBhbmQgU2VjdXJlIEVtYWlsIENBMB4XDTE5MTExOTAwMDAw MFoXDTIwMTExODIzNTk1OVowKzEpMCcGCSqGSIb3DQEJARYaZ3RheWxvckB0bmV0Y29uc3Vs dGluZy5uZXQwggEiMA0GCSqGSIb3DQEBAQUAA4IBDwAwggEKAoIBAQCwIZcEJcuE7mUfxJnD I8oOSX/TvAhoP11agD++8L7Ok8fFJhJK0lOVRsq1M6lF2E2Vzuyffg2ppbecWvHcIRadsaiG imnrJQasdkhj/JUtqPUXnC0SVA0AzYLrLReQB+9j/jTgB5JnFLyC2lEn9KTA6JmDGjvVkv2T 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