Nmingott: importing material

2025-05-12T20:36:23Z

importing material

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All the sinppets in this page require you to run
Feature require: 'OSProcess'.

=== Simple. Run a command and wait, only for the output ===

* sync
* Main issue. '''no exit code'''.

'''Example'''. ---- NO - move it out from here, requires CommandShell
out _ OSProcess outputOf: 'pwd'.
out class. "=> String "
out withBlanksTrimmed. "=> '/home/p/prog/cuis-project' "

=== Simple. Run a command and wait, only to get the exit code ===

* sync
* Main issue. '''not frequently useful'''.

'''Example'''
out _ OSProcess waitForCommand: ' sh -c "exit 33" '.
out class. "=> ExternalUnixOSProcess "
out exitCode . "=> 33 . NOTE. exitCode was added on 16-oct-2021."

=== Run a command to get the output, no input, sync ===
'''Example'''. Get the current date using Linux <code>date</code> command.
d _ Delay forMilliseconds: 50.
in _ nil.
out _ '/tmp/test.out' asFileEntry forceWriteStream .
err _ '/tmp/test.err' asFileEntry forceWriteStream .
proc _ UnixProcess forkJob: '/usr/bin/date'
arguments: nil environment: nil
descriptors: {in. out. err.}.
[proc runState == #complete] whileFalse: [d wait].
proc pid.
oExit _ proc exitCode .
oOut _ out contents.
oErr _ err contents.
{in. out. err} do: [ :f | f ifNotNil: [ f close ] ].
'exitCode: {1}, output: {2}' format: {oExit. oOut withBlanksTrimmed .}

"=> 'exitCode: 0, output: Tue 14 Sep 16:23:10 CEST 2021' "

=== Run a command through the shell to get the output, no input, sync ===
'''Example'''. Get the first 3 lines of output of <code>ls</code> in the current directory. That is run in <code>bash</code> the

command <code>ls -l | head -n 3</code>.
d _ Delay forMilliseconds: 50.
in _ nil.
out _ '/tmp/test.out' asFileEntry forceWriteStream .
err _ '/tmp/test.err' asFileEntry forceWriteStream .
proc _ UnixProcess forkJob: '/usr/bin/bash'
arguments: {'-c'. 'ls -l | head -n 3'}
environment: nil
descriptors: {in. out. err.}.
[proc runState == #complete] whileFalse: [d wait].
proc pid.
oExit _ proc exitCode .
oOut _ out contents.
oErr _ err contents.
{in. out. err} do: [ :f | f ifNotNil: [ f close ] ].
'exitCode: %d\noutput: %s' printf: {oExit. oOut withBlanksTrimmed } .
"=> 'exitCode: 0
output: total 3808
drwxrwx--- 3 p p 4096 Aug 18 12:54 AMQP
drwxrwx--- 3 p p 4096 Aug 18 12:54 Cairo' "

=== As before, but pass input through <code>stdin</code> ===
'''Example'''. We are going to count the number of charaters of what is sent through <code>stdin</code> via <code>wc -c</code>.
d _ Delay forMilliseconds: 50.
'/tmp/test.in' asFileEntry fileContents: 'Hello World!'.
in _ '/tmp/test.in' asFileEntry readStream .
out _ '/tmp/test.out' asFileEntry forceWriteStream .
err _ '/tmp/test.err' asFileEntry forceWriteStream .
proc _ UnixProcess forkJob: '/usr/bin/bash'
arguments: {'-c'. 'wc -c'}
environment: nil
descriptors: {in. out. err.}.
[proc runState == #complete] whileFalse: [d wait].
proc pid.
oExit _ proc exitCode .
oOut _ out contents.
oErr _ err contents.
{in. out. err} do: [ :f | f ifNotNil: [ f close ] ].
'exitCode: %d\noutput: %s' printf: {oExit. oOut withBlanksTrimmed } .

"=> 'exitCode: 0
output: 12' "

Run a program with OSProcess - Revision history

Nmingott: importing material