The script command in Linux and Unix (macOS)

Maria Campbell - Jul 28 - - Dev Community

Photo by Pixabay on pexels.com

This post was originally published on my personal blog mariadcampbell.com.

In my article The pipe (|) and tee commands in Linux and Unix (macOS),
I talk about how one can save the stdout resulting from a command using pipe
(|) and tee. In this article, I discuss the Linux script command. The
script command records all Terminal activity.

Running the (default) script command in Linux and Unix (macOS)

When I run the script command by typing "script" in Terminal followed by
the Return (Enter) key, the following is returned in Terminal in both
Linux and Unix (macOS):

Script started, output log file is 'typescript'
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And if I run ls on the home directory (~), the typescript file appears in
my current working directory. When I run the script command without any
args, a file called typescript is automatically created by default.
This file saves all Terminal related activity information in the
current Terminal session.

For example, if I open up the typescript file with the vim command in
Linux, it looks something like the following:

Script started on 2024-07-14 19:29:11-04:00 {TERM="xterm-256color" TTY="dev/pts/2" COLUMNS="80" LINES="24"]
^[[?2004h^[]0;maria@maria-VirtualBox: ~^G^[01;32mmaria@maria-VirtualBox^[[00m:^[[01;34m~^[[00m$ ls^M
^[[?2004l^M^[[0m^[[01;34mDesktop^[[00m  ^[[01;34mDownloads^[[00m  ^[[01;34mPictures^[[00m ^[[01;34mTemplates^[[00m  ^[[01;34mVideos^]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]...
[[5;3H^[[30m^[[47m| Please select the mail server configuration type that best meets your   ^[[97m^[[40m ^[[6;3H^[[30m^[[47m| needs.[[97m^[[40m ^[[7;3H^[[30m^[[47m|
                                              ^[[97m
                                        1872,643-553  Bot
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It is a long file, and I was not able to export the typescript file from
Linux Mint in VirtualBox into Windows 11. If anyone knows of a way of
doing that, let me know! I tried to install a an email server package, but
couldn't get beyond the configuration step. I couldn't configure it in
Terminal and couldn't exit the package configuration either.

It is basically the same process to start the script command in Unix
(macOS).

Let's say I just run the script command without any args from inside
mariadcampbell.com's local repository directory:

script
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This resulted in the following:

mariacam@Marias-MBP  ~/Development/nextjs-and-react-complete-guide/fullstack-blog   main  script

Script started, output file is typescript
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And a file called "typescript" was created inside this directory:

ls

# the following was returned:

?[38                                    jest.config.js
?[?1049l?[?25h?[                        jest.setup.js
?[?2004l??                              lib
4                                       list-directory.txt?[39m?[36D?[39m
LICENSE                                 list-directory.txt?[39m?[36D?[39m-?[39m
README.md                               list-directory.txt?[39m?[36D?[39m=?[39m
__mocks__                               next.config.js
__tests__                               node_modules
c?[38                                   package-lock.json
c?]10                                   package.json
certificates                            pages
components                              postcss.config.js
coverage                                public
data                                    scripts
demo.txt                                started
done,                                   started,
exit                                    styles
fullstack-blog-script                   tailwind.config.js
helpers                                 typescript
hooks
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The stdout of typescript looked like the following:

Script started on Mon Jul 15 12:25:21 2024
[1G[0K[1G[0K/Users/mariacam/.zshrc:110: command not found: pyenv
]1337;RemoteHost=mariacam@Marias-MBP]1337;CurrentDir=/Users/mariacam/Development/nextjs-and-react-complete-guide/fullstack-blog]1337;ShellIntegrationVersion=11;shell=zsh/Users/mariacam/.zshrc:114: command not found: pyenv
[1m[7m%[27m[1m[0m

]2;mariacam@Marias-MBP: ~/Development/nextjs-and-react-complete-guide/fullstack-blog]1;..ullstack-blog]133;D;0]1337;RemoteHost=mariacam@Marias-MBP]1337;CurrentDir=/Users/mariacam/Development/nextjs-and-react-complete-guide/fullstack-blog
[0m[27m[24m[J]133;A[39m[0m[49m[40m[39m mariacam@Marias-MBP [44m[30m[30m ~/Development/nextjs-and-react-complete-guide/fullstack-blog [43m[34m[30m  main [49m[33m[39m ]133;B[K[?1h=[?2004hll[90ms[39ml[39ms[?1l>[?2004l

]2;ls -G]1;ls]133;C;?[38                                    jest.config.js
?[?1049l?[?25h?[                        jest.setup.js
?[?2004l??                              [1m[36mlib[39;49m[0m
4                                       list-directory.txt?[39m?[36D?[39m
LICENSE                                 list-directory.txt?[39m?[36D?[39m-?[39m
README.md                               list-directory.txt?[39m?[36D?[39m=?[39m
[1m[36m__mocks__[39;49m[0m                               next.config.js
[1m[36m__tests__[39;49m[0m                               [1m[36mnode_modules[39;49m[0m
c?[38                                   package-lock.json
c?]10                                   package.json
[1m[36mcertificates[39;49m[0m                            [1m[36mpages[39;49m[0m
[1m[36mcomponents[39;49m[0m                              postcss.config.js
[1m[36mcoverage[39;49m[0m                                [1m[36mpublic[39;49m[0m
[1m[36mdata[39;49m[0m                                    [1m[36mscripts[39;49m[0m
demo.txt                                started
done,                                   started,
exit                                    [1m[36mstyles[39;49m[0m
[31mfullstack-blog-script[39;49m[0m                   tailwind.config.js
[1m[36mhelpers[39;49m[0m                                 typescript
[1m[36mhooks[39;49m[0m
[1m[7m%[27m[1m[0m

]2;mariacam@Marias-MBP: ~/Development/nextjs-and-react-complete-guide/fullstack-blog]1;..ullstack-blog]133;D;0]1337;RemoteHost=mariacam@Marias-MBP]1337;CurrentDir=/Users/mariacam/Development/nextjs-and-react-complete-guide/fullstack-blog
[0m[27m[24m[J]133;A[39m[0m[49m[40m[39m mariacam@Marias-MBP [44m[30m[30m ~/Development/nextjs-and-react-complete-guide/fullstack-blog [43m[34m[30m  main [49m[33m[39m ]133;B[K[?1h=[?2004h 90mc -l fullstack-blog-scr[90mi[90mpt[39m[K[A[93Cw[39mc[39m [39m-[39ml[39m [39mt[K[1B
[K[A[102Cypescript[?1l>[?2004l[1B
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If I wanted to find out how many lines typescript contains, I ran the
following command:

wc -l typescript
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which returns:

24 typescript
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This means that the file contains 24 lines. And if I run the exit command,
the following is returned:

Script done, output file is typescript
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And if I then run wc -l typescript again, it returns the following:

28 typescript
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That is because the exit command is appended to the end of the
typescript file.

]2;wc -l typescript]1;wc]133;C;      24 typescript
[1m[7m%[27m[1m[0m

]2;mariacam@Marias-MBP: ~/Development/nextjs-and-react-complete-guide/fullstack-blog]1;..ullstack-blog]133;D;0]1337;RemoteHost=mariacam@Marias-MBP]1337;CurrentDir=/Users/mariacam/Development/nextjs-and-react-complete-guide/fullstack-blog
[0m[27m[24m[J]133;A[39m[0m[49m[40m[39m mariacam@Marias-MBP [44m[30m[30m ~/Development/nextjs-and-react-complete-guide/fullstack-blog [43m[34m[30m  main [49m[33m[39m ]133;B[K[?1h=[?2004hee[90mxit[39me[39mx[39mi[39mt[?1l>[?2004l

]2;exit]1;exit]133;C;
Script done on Mon Jul 15 12:29:28 2024
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Running custom scripts in Unix (macOS)

Now let's say I want to do things a bit differently, follow a different script
(other than script itself) inside my fullstack-blog directory which houses
the local repo for mariadcampbell.com:

npm run dev 2>&1 | tee ~/desktop/full-stack-blog.txt
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Instead of using the script command, I am using a "custom script". In
fact, it is an npm local script located in my package.json file for
mariadcampbell.com. The following then is returned in Terminal:

 fullstack-blog@0.1.0 dev
> next dev

  ▲ Next.js 14.2.4
  - Local:        http://localhost:3000
  - Environments: .env.development.local, .env.local, .env

 ✓ Starting...
 ✓ Ready in 1241ms
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The custom script resulted in first running the npm run dev command
and starting up the development server for fullstack-blog in the
browser, and the stdout to Terminal is the following above. But since I
also use pipe | and tee, it resulted in the creation of a file
called fullstack-blog.txt on the desktop, and it contained the
following:


> fullstack-blog@0.1.0 dev
> next dev

  ▲ Next.js 14.2.4
  - Local:        http://localhost:3000
  - Environments: .env.development.local, .env.local, .env

 ✓ Starting...
 ✓ Ready in 1241ms
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which is the same as stdout to Terminal!

In addition, I am redirecting any errors that may occur to
fullstack-blog.txt as well. 2 points to stderr. 1 points to stdout.
And 2>&1 redirects npm run dev stdout and stderr to
fullstack-blog.txt. Specifically, 2>&1 means redirect stderr to
stdout, and both are stdin for the tee command, which basically copies
and pastes stdout to a specified file. In this case, fullstack-blog.txt.

Let's say I wanted to stop npm run dev, thereby stop redirecting it to
the fullstack-blog.txt file. I simply press the Control key + C key like I
would normally when I want to stop running the development server. But if
I simply ran npm run dev afterwards, the stdout to Terminal would no
longer be redirected to fullstack-blog.txt. I would have to re-run
npm run dev 2>&1 | tee ~/desktop/full-stack-blog.txt. And if I want to
append new stdout to the end of the file instead of overwriting it,
the default behavior of the tee command, I would run the following
instead:

npm run dev 2>&1 | tee -a ~/desktop/full-stack-blog.txt
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And now the stdout of fullstack-blog.txt is the following:

> fullstack-blog@0.1.0 dev
> next dev

  ▲ Next.js 14.2.4
  - Local:        http://localhost:3000
  - Environments: .env.development.local, .env.local, .env

 ✓ Starting...
 ✓ Ready in 1241ms

> fullstack-blog@0.1.0 dev
> next dev

  ▲ Next.js 14.2.4
  - Local:        http://localhost:3000
  - Environments: .env.development.local, .env.local, .env

 ✓ Starting...
 ✓ Ready in 1154ms
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The same can be done with any script that you want to save to a file.
This way, if you want to be able to refer back to the
logging information and find out what went wrong, for example, or
perhaps what went right, you could refer to the .txt file that the
stdout was redirected to, written to, and saved. For
nextjs developers, for example, or developers in general, doing this
with the build script, the production server post-build, the
test script, any linting scripts, etc., is very useful.

If I make my way around my nextjs application in the browser, this is
logged as well. I visited a couple of pages and posts, and since I was using
the -a or --append flag, the new stdout was added to the end of the
fullstack-blog.txt file:

> fullstack-blog@0.1.0 dev
> next dev

  ▲ Next.js 14.2.4
  - Local:        http://localhost:3000
  - Environments: .env.development.local, .env.local, .env

 ✓ Starting...
 ✓ Ready in 1241ms

> fullstack-blog@0.1.0 dev
> next dev

  ▲ Next.js 14.2.4
  - Local:        http://localhost:3000
  - Environments: .env.development.local, .env.local, .env

 ✓ Starting...
 ✓ Ready in 1154ms
 ○ Compiling / ...
 ✓ Compiled / in 618ms (816 modules)
Warning: data for page "/" is 132 kB which exceeds the threshold of 128 kB, this amount of data can reduce performance.
See more info here: https://nextjs.org/docs/messages/large-page-data
 GET / 200 in 926ms
 ✓ Compiled /about in 185ms (823 modules)
 ✓ Compiled /blog in 163ms (839 modules)
Warning: data for page "/blog" is 1.28 MB which exceeds the threshold of 128 kB, this amount of data can reduce performance.
See more info here: https://nextjs.org/docs/messages/large-page-data
 GET /_next/data/development/blog.json 200 in 104ms
 ✓ Compiled /_error in 71ms (841 modules)
 GET /images/blog/the-script-command-in-linux-and-unix-macos/undefined 404 in 103ms
 ⨯ The requested resource isn't a valid image for /images/blog/the-script-command-in-linux-and-unix-macos/undefined received text/html; charset=utf-8
Warning: data for page "/" is 132 kB which exceeds the threshold of 128 kB, this amount of data can reduce performance.
See more info here: https://nextjs.org/docs/messages/large-page-data
 GET /_next/data/development/index.json 200 in 51ms
 ○ Compiling /blog/[slug] ...
 ✓ Compiled /blog/[slug] in 644ms (1644 modules)
 GET /_next/data/development/blog/using-pipe-and-grep-in-linux-and-unix-macos.json?slug=using-pipe-and-grep-in-linux-and-unix-macos 200 in 1036ms
Warning: data for page "/blog" is 1.28 MB which exceeds the threshold of 128 kB, this amount of data can reduce performance.
See more info here: https://nextjs.org/docs/messages/large-page-data
 GET /_next/data/development/blog.json 200 in 143ms
 GET /images/blog/the-script-command-in-linux-and-unix-macos/undefined 404 in 7ms
 ⨯ The requested resource isn't a valid image for /images/blog/the-script-command-in-linux-and-unix-macos/undefined received text/html; charset=utf-8
 GET /_next/data/development/blog/the-script-command-in-linux-and-unix-macos.json?slug=the-script-command-in-linux-and-unix-macos 200 in 16ms
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This is much longer than the previous stdout I shared here!

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