Sponsored Content
Full Discussion: "let" in BASH
Top Forums Shell Programming and Scripting "let" in BASH Post 302915039 by Perderabo on Saturday 30th of August 2014 11:01:41 PM
Old 08-31-2014
The "let" command originated in ksh. Dave Korn considered it to be a mistake and very quickly developed the double parentheses notation to replace it. By the mid 1980's the advice was to not use the "let" command in new code. However the let command is still available. It is intended for legacy code. bash copied ksh arithmetic including both the double parentheses and the "let" command. And the bash team followed Dave's lead in not recommending the "let" command.

I started using ksh in the late 80's. The "let" command had been deprecated for several years even back then. I have been writing ksh scripts form over a quarter of a century. I don't believe that I have ever used "let". I don't believe that I ever will.
These 2 Users Gave Thanks to Perderabo For This Post:
 

9 More Discussions You Might Find Interesting

1. UNIX for Dummies Questions & Answers

Explain the line "mn_code=`env|grep "..mn"|awk -F"=" '{print $2}'`"

Hi Friends, Can any of you explain me about the below line of code? mn_code=`env|grep "..mn"|awk -F"=" '{print $2}'` Im not able to understand, what exactly it is doing :confused: Any help would be useful for me. Lokesha (4 Replies)
Discussion started by: Lokesha
4 Replies

2. Shell Programming and Scripting

Simplify Bash Script Using "sed" Or "awk"

Input file: 2 aux003.net3.com error12 6 awn0117.net1.com error13 84 aux008 error14 29 aux001.ha.ux.isd.com error12 209 aux002.vm.ux.isd.com error34 21 alx0027.vm.net2.com error12 227 dux001.net5.com error123 22 us008.dot.net2.com error121 13 us009.net2.com error129Expected Output: 2... (4 Replies)
Discussion started by: sQew
4 Replies

3. Shell Programming and Scripting

awk command to replace ";" with "|" and ""|" at diferent places in line of file

Hi, I have line in input file as below: 3G_CENTRAL;INDONESIA_(M)_TELKOMSEL;SPECIAL_WORLD_GRP_7_FA_2_TELKOMSEL My expected output for line in the file must be : "1-Radon1-cMOC_deg"|"LDIndex"|"3G_CENTRAL|INDONESIA_(M)_TELKOMSEL"|LAST|"SPECIAL_WORLD_GRP_7_FA_2_TELKOMSEL" Can someone... (7 Replies)
Discussion started by: shis100
7 Replies

4. UNIX for Dummies Questions & Answers

"Help with bash script" - "License Server and Patch Updates"

Hi All, I'm completely new to bash scripting and still learning my way through albeit vey slowly. I need to know where to insert my server names', my ip address numbers through out the script alas to no avail. I'm also searching on how to save .sh (bash shell) script properly.... (25 Replies)
Discussion started by: profileuser
25 Replies

5. UNIX for Dummies Questions & Answers

Using "mailx" command to read "to" and "cc" email addreses from input file

How to use "mailx" command to do e-mail reading the input file containing email address, where column 1 has name and column 2 containing “To” e-mail address and column 3 contains “cc” e-mail address to include with same email. Sample input file, email.txt Below is an sample code where... (2 Replies)
Discussion started by: asjaiswal
2 Replies

6. Shell Programming and Scripting

Mindboggling difference between using "tee" and "/usr/bin/tee" in bash

I'm on Ubuntu 14.04 and I manually updated my coreutils so that "tee" is now on version 8.27 I was running a script using bash where there is some write to pipe error at some point causing the tee command to exit abruptly while the script continues to run. The newer version of tee seems to prevent... (2 Replies)
Discussion started by: stompadon
2 Replies

7. Shell Programming and Scripting

Explaining behaviour of sudo bash "$0" "$@";

I've found this script part on the stackoverflow: if ; then sudo bash "$0" "$@"; exit "$?"; fi I realized that sudo bash "$0" "$@"; is the only needed for me. But the strange thing happens when I move this line outside the IF statement: sudo bash "$0" "$@"; stops the... (9 Replies)
Discussion started by: boqsc
9 Replies

8. Shell Programming and Scripting

Bash script - Print an ascii file using specific font "Latin Modern Mono 12" "regular" "9"

Hello. System : opensuse leap 42.3 I have a bash script that build a text file. I would like the last command doing : print_cmd -o page-left=43 -o page-right=22 -o page-top=28 -o page-bottom=43 -o font=LatinModernMono12:regular:9 some_file.txt where : print_cmd ::= some printing... (1 Reply)
Discussion started by: jcdole
1 Replies

9. AIX

Apache 2.4 directory cannot display "Last modified" "Size" "Description"

Hi 2 all, i have had AIX 7.2 :/# /usr/IBMAHS/bin/apachectl -v Server version: Apache/2.4.12 (Unix) Server built: May 25 2015 04:58:27 :/#:/# /usr/IBMAHS/bin/apachectl -M Loaded Modules: core_module (static) so_module (static) http_module (static) mpm_worker_module (static) ... (3 Replies)
Discussion started by: penchev
3 Replies
UDISKSCTL(1)							   User Commands						      UDISKSCTL(1)

NAME
udisksctl - The udisks command line tool SYNOPSIS
udisksctl status udisksctl info {--object-path OBJECT | --block-device DEVICE} udisksctl mount {--object-path OBJECT | --block-device DEVICE} [--filesystem-type TYPE] [--options OPTIONS...] [--no-user-interaction] udisksctl unmount {--object-path OBJECT | --block-device DEVICE} [--force] [--no-user-interaction] udisksctl unlock {--object-path OBJECT | --block-device DEVICE} [--no-user-interaction] udisksctl lock {--object-path OBJECT | --block-device DEVICE} [--no-user-interaction] udisksctl loop-setup --file PATH [--read-only] [--offset OFFSET] [--size SIZE] [--no-user-interaction] udisksctl loop-delete {--object-path OBJECT | --block-device DEVICE} [--no-user-interaction] udisksctl smart-simulate --file PATH {--object-path OBJECT | --block-device DEVICE} [--no-user-interaction] udisksctl monitor udisksctl dump udisksctl help DESCRIPTION
udisksctl is a command-line program used to interact with the udisksd(8) daemon process. COMMANDS
status Shows high-level information about disk drives and block devices. info Shows detailed information about OBJECT or DEVICE. mount Mounts a device. The device will be mounted in a subdirectory in the /media hierarchy - upon successful completion, the mount point will be printed to standard output. The device will be mounted with a safe set of default options. You can influence the options passed to the mount(8) command with --options. Note that only safe options are allowed - requests with inherently unsafe options such as suid or dev that would allow the caller to gain additional privileges, are rejected. unmount Unmounts a device. This only works if the device is mounted. The option --force can be used to request that the device is unmounted even if active references exists. unlock Unlocks an encrypted device. The passphrase will be requested from the controlling terminal and upon successful completion, the cleartext device will be printed to standard output. lock Locks a device. This only works if the device is a cleartext device backed by a cryptotext device. loop-setup Sets up a loop device backed by FILE. loop-delete Tears down a loop device. smart-simulate Sets SMART data from the libatasmart blob given by FILE - see /usr/share/doc/libatasmart-devel-VERSION/ for blobs shipped with libatasmart. This is a debugging feature used to check that applications act correctly when a disk is failing. monitor Monitors the daemon for events. dump Prints the current state of the daemon. help Prints help and exit. COMMON OPTIONS
The option --no-user-interaction can be used to request that no interaction (such as the user being presented with an authentication dialog) must occur when checking with polkit(8) whether the caller is authorized to perform the requested action. AUDIENCE
This program does not assume that the caller is the super user - it is intended to be used by unprivileged users and authorizations are checked by the udisks daemon using polkit(8). Additionally, this program is not intended to be used by scripts or other programs - options/commands may change in incompatible ways in the future even in maintenance releases. See the "API STABILITY" section of udisks(8) for more information. BASH COMPLETION
udisksctl ships with a bash completion script to complete commands, objects, block devices and some options. AUTHOR
Written by David Zeuthen <zeuthen@gmail.com> with a lot of help from many others. BUGS
Please send bug reports to either the distribution bug tracker or the upstream bug tracker at http://bugs.freedesktop.org/enter_bug.cgi?product=udisks. SEE ALSO
udisks(8), udisksd(8), umount.udisks2(8), polkit(8) udisks 2.1.2 March 2013 UDISKSCTL(1)
All times are GMT -4. The time now is 04:56 PM.
Unix & Linux Forums Content Copyright 1993-2022. All Rights Reserved.
Privacy Policy