Mediaflux TCL script: loop through query results with cursors

set size 100
set idx 1
set remaining 1

while { $remaining > 0 } {
    set r [asset.query :size $size :idx $idx :count true :where "namespace>=/test"]
    foreach id [xvalues id $r] {
         puts $id
    set idx [expr { $idx + $size }]
    set remaining [xvalue cursor/remaining $r]

Python pysftp: bypass ssh host key verification

import pysftp

cnopts = pysftp.CnOpts();

# set hostkeys to None to disable ssh key verification
cnopts.hostkeys = None
   sftp = pysftp.Connection(host='', username='sftp-user', password='password', port=22, cnopts=cnopts)
   if sftp:

Windows Batch Script: remove trailing slash from a path string

set "a=C:\Users\wx\Downloads\"
if "%a:~-1%"=="\" set "a=%a:~0,-1%"
if "%a:~-1%"=="/" set "a=%a:~0,-1%"
echo %a%

see also

Windows Batch Script: parse arguments

@echo off
setlocal EnableExtensions EnableDelayedExpansion

set verbose=false
set value=

if "%~1"=="" (
    if "%~1"=="--help" (
        call :help
        exit /b 0
    if "%~1"=="--value" (
        set value=%~2
        goto :loop
    if "%~1"=="--verbose" (
        set verbose=true
        goto :loop
    goto :loop

see also

Windows Batch Script: check if argument exists

if "%~1"=="" ( echo exists ) else ( echo not exist )

Windows Batch Script: command argument expansion

expands %I removing any surrounding quotes:
%~I         - expands %I removing any surrounding quotes (")
%~fI        - expands %I to a fully qualified path name
%~dI        - expands %I to a drive letter only
%~pI        - expands %I to a path only
%~nI        - expands %I to a file name only
%~xI        - expands %I to a file extension only
%~sI        - expanded path contains short names only
%~aI        - expands %I to file attributes of file
%~tI        - expands %I to date/time of file
%~zI        - expands %I to size of file
%~$PATH:I   - searches the directories listed in the PATH
               environment variable and expands %I to the
               fully qualified name of the first one found.
               If the environment variable name is not
               defined or the file is not found by the
               search, then this modifier expands to the
               empty string

Windows Batch Script: string operations

  • substring:
    set "var=apple pear"
    echo %var~6,4%
    REM pear
    echo %var~0,-5% 
    REM apple
  • replace character:
    set "var=a,b,c"
    REM replace commas with spaces
    echo %var:,= %
    REM a b c

see also

Windows Batch Script: comma in command arguments

Comma (or semicolon) in command arguments, if not quoted, are considered separators (same as white space). See the script (named test.bat) below:
@echo off
if not "%~1"=="" (
    echo %~1 
    goto :loop
When calling the script,
if not quoted:
test.bat 1,2,3

if quoted:
test.bat "1,2,3"

Windows Batch Script: enable delayed expansion

In compound code blocks, with setting EnableDelayedExpansion, the current value will NOT assigned to the variable as expected. see the code below:
set var=1
set switch=on

if "%switch%"=="on" (
   set var=2
   echo %var%
   REM it prints 1
It actually prints the original value 1. To avoid such unexpected behaviour, you need to set EnableDelayedExpansion, and using !var!:
setlocal EnableDelayedExpansion
set var=1
set switch=on

if "%switch%"=="on" (
   set var=2
   echo !var!
   REM it prints 2

see also

Windows Batch Script: split comma delimited string and loop through the tokens


SET emails=%emails:,= %

FOR %%e in (%emails%) DO (
    echo %%e

Windows Batch Script: replace a character in string

SET str=1,2,3,4

REM replace comma with blank space
SET str=%str:,= %
ECHO %str%

see also

Windows Batch Script: get the script file name


  • ~ -- strip/trim quotes off
  • d -- drive
  • p -- path
  • n -- file name
  • x -- extension
  • f -- full path


suppose I have a script file at C:\Users\WXYZ\Documents\test.cmd
REM test.cmd
ECHO %~0

REM test
ECHO %~n0

REM .cmd
ECHO %~x0

REM C:\Users\WXYZ\test.cmd
ECHO %~dpf0

REM C:\Users\WXYZ\test.cmd
ECHO %~dpnx0

REM C:\Users\WXYZ\test
ECHO %~dpn0

REM C:\Users\WXYZ\
ECHO %~dp0

see also

Windows Batch Script: escape special characters in ECHO

REM This is a <test>
ECHO This is a ^<test^>

see also

Windows Batch Script: IF THEN ELSE

    ECHO success
) ELSE (
    ECHO failure

Shell script: parse arguments

The best answer:

BASH script: split string to array

IFS=',' read -r -a array <<< "$str"

for e in "${array[@]}"
    echo $e

see also

Shell scripting: extract substring (or path components) from string in BASH

str="I like shell scripting."

echo ${str:7:5} # 7 is offset, 5 is length, it will print shell

echo ${path#*/}     # trim the prefix: a/b/c
echo ${path#/a/}    # trim the prefix: b/c
echo ${path#$root/} # trim the prefix: b/c
echo ${path#*b}     # trim the prefix: /c

echo ${name%/*}   # trim the suffix: /a/b
echo ${name%.txt} # trim the suffix: /a/b/c

see also

Shell scripting: loop through an array or positional access

# declare a empty array
declare -a array1=()


echo ${array1[0]} # foo
echo ${array1[1]} # bar

for elem in "${array1[@]}"
    echo $elem

Shell scripting: append element to array

declare -a array1=()

for elem in "${array1[@]}"
    echo $elem

Shell scripting: check if an array is empty

declare -a array1=()

if [[ ${#array1[@]} -eq 0 ]]; then
    echo "array1 is empty"

echo "array1 has ${#array1[@]} elements"

echo "array1 has ${#array1[@]} elements"

Windows Batch Script: download file using bitsadmin without ssl certification validation

  • For the web server that does not support content range requests. You have to set priority to FOREGROUND to force the job to run synchronously. Otherwise, error: BG_E_INSUFFICIENT_RANGE_SUPPORT (0x80200013)
    bitsadmin /transfer MyJob /priority FOREGROUND  "" "C:\test\"
  • For the web server with self signed certificate or could not pass the ssl certificate validation, you cannot use a single bitsadmin /transfer command and the job has to be run asynchronously. You have to bitsadmin /create a job and bitsadmin /SetSecurityFlags to value 30
    bitsadmin /create MyJob1
    bitsadmin /addfile MyJob1 "" "C:\test\"
    bitsadmin /SetSecurityFlags MyJob1 30
    bitsadmin /SetPriority MyJob1 FOREGROUND
    bitsadmin /resume MyJob1
    bitsadmin /monitor || bitsadmin /cancel MyJob1

see also

curl and wget: bypass ssl certification validation

  • --insecure or -k for curl:
    curl --create-dirs -k -o /path/to/output-dir/file
  • --no-check-certificate for wget:
    wget --no-check-certificate -O /path/to/output-dir/file

curl and wget: create parent directories

curl --create-dirs -o "/path/to/output-dir/file.txt" ""
mkdir -p "/path/to/output-dir" && wget --no-check-certificate -O "/path/to/output-dir/file.txt" ""

Bash scripting: check whether the script is sourced or executed in subshell

if [[ "${BASH_SOURCE[0]}" != "${0}" ]]; then
    echo "sourced"
    echo "executed"

The example below, call return if the script is sourced otherwise call exit:
my_func1 || ( if [[ "${BASH_SOURCE[0]}" != "${0}" ]]; then return 1; else exit 1 )

see also


Shell Script: if then else in one line

if [[ ${a} -ge 0 ]]; then echo "positive number"; else echo "negative number"; fi

if [[ $? -ne 0 ]]; then echo "failure"; else echo "success"; fi

Windows Batch Script: Download file using powershell

SET "url="
SET "out=C:\Downloads"
POWERSHELL -COMMAND "[System.Net.ServicePointManager]::ServerCertificateValidationCallback = {$true};(New-Object Net.WebClient).DownloadFile('%url%', '%out%')"
NOTE: [System.Net.ServicePointManager]::ServerCertificateValidationCallback = {$true} bypass the SSL certificate validation.

See also

Windows Batch Script: call multiple powershell commands in one line

Multiple powershell commands are separated by semicolons:
POWERSHELL -COMMAND "[System.Net.ServicePointManager]::ServerCertificateValidationCallback = {$true};(New-Object Net.WebClient).DownloadFile('%url%', '%out%')"

Windows Batch Script: conditional exit one line

CALL :FUNC1 || ( ECHO "Error: exit code=%ERRORLEVEL%" && EXIT /B 1 )

Windows Batch Script: Create directories recursively

SETLOCAL EnableExtensions
SET dir="C:\A\B\C"
MD "%dir%"

Windows Batch Script: dirname equivalent, get the parent directory of a file

Note: the code below can handle the path contains spaces:
  • Option 1:
    SET filename="C:\Files\A Dir\file1.txt"
    FOR %%F IN (%filename%) DO SET "dirname=%%~dpF"
    ECHO %dirname%
  • Option 2:
    SET "filename=C:\Files\A Dir\file1.txt"
    FOR %%F IN ("%filename%") DO SET "dirname=%%~dpF"
    ECHO %dirname%