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WriteLine
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WriteLine

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WriteLine["file","string"]

writes "string" to a file, followed by a newline.

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WriteLine[stream,"string"]

writes "string", followed by a newline, to the specified output stream.

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WriteLine[proc,"string"]

writes "string" to an external process proc.

Details

  • WriteLine will open a file for writing, erasing all existing data, if it is not already open.
  • WriteLine[File["file"],…] is also supported.

Examples

open allclose all

Basic Examples  (2)Summary of the most common use cases

Write a string to a temporary file:

In[1]:=1
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https://wolfram.com/xid/0cq0593o-m161nx
In[2]:=2
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https://wolfram.com/xid/0cq0593o-ueucmp

Print the file:

In[3]:=3
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https://wolfram.com/xid/0cq0593o-fki5o2

Delete the temporary file:

In[4]:=4
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https://wolfram.com/xid/0cq0593o-w78j1n

Start the system shell process:

In[1]:=1
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https://wolfram.com/xid/0cq0593o-hp8oi3
Out[1]=1

Write a command into the shell process:

In[2]:=2
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https://wolfram.com/xid/0cq0593o-6j3c93

Read one line from the shell output:

In[3]:=3
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https://wolfram.com/xid/0cq0593o-32mxq4
Out[3]=3

Scope  (2)Survey of the scope of standard use cases

Open a stream:

In[1]:=1
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https://wolfram.com/xid/0cq0593o-3yu61f

Write a line into the file:

In[2]:=2
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https://wolfram.com/xid/0cq0593o-omarha

Close the stream:

In[3]:=3
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https://wolfram.com/xid/0cq0593o-har5cs

Print the contents that were written:

In[4]:=4
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https://wolfram.com/xid/0cq0593o-dzxlkv

Create a temporary file:

In[1]:=1
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https://wolfram.com/xid/0cq0593o-wvotax
Out[1]=1

Write a line of text:

In[2]:=2
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https://wolfram.com/xid/0cq0593o-3xpaee
In[3]:=3
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https://wolfram.com/xid/0cq0593o-pcw9o4
In[4]:=4
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https://wolfram.com/xid/0cq0593o-6hnod4
Out[4]=4

Both lines were written:

In[5]:=5
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https://wolfram.com/xid/0cq0593o-9fyp57

Delete the temporary file:

In[6]:=6
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https://wolfram.com/xid/0cq0593o-0qc71o

Properties & Relations  (1)Properties of the function, and connections to other functions

WriteLine inserts line breaks after each string it writes:

In[1]:=1
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https://wolfram.com/xid/0cq0593o-xtaiq1
Out[1]=1
In[2]:=2
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https://wolfram.com/xid/0cq0593o-54v9k8
Out[4]=4
In[5]:=5
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https://wolfram.com/xid/0cq0593o-6lrykk

WriteString does not insert line breaks automatically:

In[6]:=6
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https://wolfram.com/xid/0cq0593o-r9vzz
Out[8]=8
In[9]:=9
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https://wolfram.com/xid/0cq0593o-t2tiup

Delete the temporary file:

In[10]:=10
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https://wolfram.com/xid/0cq0593o-k04n4g
Wolfram Research (2014), WriteLine, Wolfram Language function, https://reference.wolfram.com/language/ref/WriteLine.html (updated 2016).
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Wolfram Research (2014), WriteLine, Wolfram Language function, https://reference.wolfram.com/language/ref/WriteLine.html (updated 2016).

Text

Wolfram Research (2014), WriteLine, Wolfram Language function, https://reference.wolfram.com/language/ref/WriteLine.html (updated 2016).

✖
Wolfram Research (2014), WriteLine, Wolfram Language function, https://reference.wolfram.com/language/ref/WriteLine.html (updated 2016).

CMS

Wolfram Language. 2014. "WriteLine." Wolfram Language & System Documentation Center. Wolfram Research. Last Modified 2016. https://reference.wolfram.com/language/ref/WriteLine.html.

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Wolfram Language. 2014. "WriteLine." Wolfram Language & System Documentation Center. Wolfram Research. Last Modified 2016. https://reference.wolfram.com/language/ref/WriteLine.html.

APA

Wolfram Language. (2014). WriteLine. Wolfram Language & System Documentation Center. Retrieved from https://reference.wolfram.com/language/ref/WriteLine.html

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Wolfram Language. (2014). WriteLine. Wolfram Language & System Documentation Center. Retrieved from https://reference.wolfram.com/language/ref/WriteLine.html

BibTeX

@misc{reference.wolfram_2025_writeline, author="Wolfram Research", title="{WriteLine}", year="2016", howpublished="\url{https://reference.wolfram.com/language/ref/WriteLine.html}", note=[Accessed: 02-June-2025 ]}

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@misc{reference.wolfram_2025_writeline, author="Wolfram Research", title="{WriteLine}", year="2016", howpublished="\url{https://reference.wolfram.com/language/ref/WriteLine.html}", note=[Accessed: 02-June-2025 ]}

BibLaTeX

@online{reference.wolfram_2025_writeline, organization={Wolfram Research}, title={WriteLine}, year={2016}, url={https://reference.wolfram.com/language/ref/WriteLine.html}, note=[Accessed: 02-June-2025 ]}

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@online{reference.wolfram_2025_writeline, organization={Wolfram Research}, title={WriteLine}, year={2016}, url={https://reference.wolfram.com/language/ref/WriteLine.html}, note=[Accessed: 02-June-2025 ]}