diff --git a/README.md b/README.md
index 7abe42f..9a03ccf 100644
--- a/README.md
+++ b/README.md
@@ -73,6 +73,7 @@ As part of building the import server, the following commands exercise each oper
 - [x] trello stack get - includes list of cards
 - [x] trello card get - includes list of attachments
 - [x] trello attachment get - includes download url
+- [x] trello attachment save - saves to disk
 - [ ] nextcloud deck get (was board list)
 - [ ] nextcloud board get (was stack list)
 - [ ] nextcloud stack get (was card list)
diff --git a/src/lib.rs b/src/lib.rs
index b49aac8..8aec10c 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -67,10 +67,10 @@ pub struct Ctx {
     pub net: Net,
     pub prt: Printer,
 }
-impl Default for Ctx {
-    fn default() -> Self {
+impl Ctx {
+    pub fn new(base: impl Into<PathBuf>) -> Self {
         Self {
-            fs: kxio::fs::new(PathBuf::default()),
+            fs: kxio::fs::new(base),
             net: kxio::net::new(),
             prt: kxio::print::standard(),
         }
@@ -79,7 +79,7 @@ impl Default for Ctx {
 
 #[derive(Clone)]
 pub(crate) struct FullCtx {
-    // pub fs: FileSystem,
+    pub fs: FileSystem,
     pub net: Net,
     pub prt: Printer,
     pub cfg: AppConfig,
@@ -121,7 +121,7 @@ pub async fn run(ctx: Ctx) -> color_eyre::Result<()> {
             commands
                 .command
                 .execute(FullCtx {
-                    // fs: ctx.fs,
+                    fs: ctx.fs,
                     net: ctx.net,
                     prt: ctx.prt,
                     cfg,
diff --git a/src/main.rs b/src/main.rs
index d253395..7b8210e 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -6,5 +6,5 @@ use trello_to_deck::{run, Ctx};
 #[tokio::main]
 #[cfg_attr(test, mutants::skip)]
 async fn main() -> Result<()> {
-    run(Ctx::default()).await
+    run(Ctx::new(std::env::current_dir()?)).await
 }
diff --git a/src/nextcloud/tests.rs b/src/nextcloud/tests.rs
index 883a6bf..893e4f8 100644
--- a/src/nextcloud/tests.rs
+++ b/src/nextcloud/tests.rs
@@ -118,8 +118,8 @@ mod commands {
                 .body(include_str!("../tests/responses/nextcloud-board-list.json"))
                 .expect("mock request");
 
-            // let fs = given::a_filesystem();
-            let ctx = given::a_full_context(mock_net);
+            let fs = given::a_filesystem();
+            let ctx = given::a_full_context(mock_net, fs);
             let prt = ctx.prt.clone();
             let prt = prt.as_test().unwrap();
 
@@ -151,8 +151,8 @@ mod commands {
                 .body(include_str!("../tests/responses/nextcloud-board-list.json"))
                 .expect("mock request");
 
-            // let fs = given::a_filesystem();
-            let ctx = given::a_full_context(mock_net);
+            let fs = given::a_filesystem();
+            let ctx = given::a_full_context(mock_net, fs);
             let prt = ctx.prt.clone();
             let prt = prt.as_test().unwrap();
 
@@ -195,8 +195,8 @@ mod commands {
                 ))
                 .expect("mock request");
 
-            // let fs = given::a_filesystem();
-            let ctx = given::a_full_context(mock_net);
+            let fs = given::a_filesystem();
+            let ctx = given::a_full_context(mock_net, fs);
 
             //when
             let result = ctx
@@ -220,8 +220,8 @@ mod commands {
                 .body(include_str!("../tests/responses/nextcloud-stack-list.json"))
                 .expect("mock request");
 
-            // let fs = given::a_filesystem();
-            let ctx = given::a_full_context(mock_net);
+            let fs = given::a_filesystem();
+            let ctx = given::a_full_context(mock_net, fs);
 
             //when
             let result = ctx
@@ -332,8 +332,8 @@ mod commands {
                 .body(include_str!("../tests/responses/nextcloud-card-list.json"))
                 .expect("mock request");
 
-            // let fs = given::a_filesystem();
-            let ctx = given::a_full_context(mock_net);
+            let fs = given::a_filesystem();
+            let ctx = given::a_full_context(mock_net, fs);
 
             //when
             let result = ctx
@@ -378,8 +378,8 @@ mod commands {
                 .body(include_str!("../tests/responses/nextcloud-card-get.json"))
                 .expect("mock request");
 
-            // let fs = given::a_filesystem();
-            let ctx = given::a_full_context(mock_net);
+            let fs = given::a_filesystem();
+            let ctx = given::a_full_context(mock_net, fs);
 
             //when
             let result = ctx
@@ -432,8 +432,8 @@ mod commands {
                 ))
                 .expect("mock request");
 
-            // let fs = given::a_filesystem();
-            let ctx = given::a_full_context(mock_net);
+            let fs = given::a_filesystem();
+            let ctx = given::a_full_context(mock_net, fs);
 
             //when
             let result = ctx
@@ -484,8 +484,8 @@ mod commands {
                 .mock()
                 .expect("mock request");
 
-            // let fs = given::a_filesystem();
-            let ctx = given::a_full_context(mock_net);
+            let fs = given::a_filesystem();
+            let ctx = given::a_full_context(mock_net, fs);
 
             //when
             let result = ctx
diff --git a/src/tests/mod.rs b/src/tests/mod.rs
index e12f7e6..c93f685 100644
--- a/src/tests/mod.rs
+++ b/src/tests/mod.rs
@@ -131,12 +131,9 @@ pub(crate) mod given {
         Ctx { fs, net, prt }
     }
 
-    pub(crate) fn a_full_context(
-        mock_net: MockNet,
-        // fs: TempFileSystem
-    ) -> FullCtx {
+    pub(crate) fn a_full_context(mock_net: MockNet, fs: TempFileSystem) -> FullCtx {
         FullCtx {
-            // fs: fs.as_real(),
+            fs: fs.as_real(),
             net: mock_net.into(),
             prt: a_printer(),
             cfg: AppConfig {
diff --git a/src/tests/responses/trello-attachment-save.png b/src/tests/responses/trello-attachment-save.png
new file mode 100644
index 0000000..2f10201
Binary files /dev/null and b/src/tests/responses/trello-attachment-save.png differ
diff --git a/src/trello/attachment.rs b/src/trello/attachment.rs
index cbd661b..4ec8644 100644
--- a/src/trello/attachment.rs
+++ b/src/trello/attachment.rs
@@ -1,3 +1,5 @@
+use std::path::PathBuf;
+
 //
 use clap::Parser;
 use color_eyre::Result;
@@ -15,6 +17,11 @@ pub(crate) enum TrelloAttachmentCommand {
         card_id: String,
         attachment_id: String,
     },
+    Save {
+        card_id: String,
+        attachment_id: String,
+        file_name: Option<PathBuf>, // will use file name from attachment if not provided.
+    },
 }
 
 impl Execute for TrelloAttachmentCommand {
@@ -25,12 +32,11 @@ impl Execute for TrelloAttachmentCommand {
                 card_id,
                 attachment_id,
             } => {
+                let trello_card_id = TrelloCardId::new(card_id);
+                let trello_attachment_id = TrelloAttachmentId::new(attachment_id);
                 let api_result = ctx
                     .trello_client()
-                    .card_attachment(
-                        &TrelloCardId::new(card_id),
-                        &TrelloAttachmentId::new(attachment_id),
-                    )
+                    .card_attachment(&trello_card_id, &trello_attachment_id)
                     .await;
                 if dump {
                     p!(ctx.prt, "{}", api_result.text);
@@ -40,6 +46,20 @@ impl Execute for TrelloAttachmentCommand {
                 }
                 Ok(())
             }
+            Self::Save {
+                card_id,
+                attachment_id,
+                file_name,
+            } => {
+                let trello_card_id = TrelloCardId::new(card_id);
+                let trello_attachment_id = TrelloAttachmentId::new(attachment_id);
+                let file_name = ctx
+                    .trello_client()
+                    .save_attachment(&trello_card_id, &trello_attachment_id, file_name)
+                    .await?;
+                p!(ctx.prt, "Wrote: {}", file_name.display());
+                Ok(())
+            }
         }
     }
 }
diff --git a/src/trello/client.rs b/src/trello/client.rs
index d6f5573..f0d2739 100644
--- a/src/trello/client.rs
+++ b/src/trello/client.rs
@@ -1,6 +1,8 @@
 //
 use std::collections::HashMap;
+use std::path::PathBuf;
 
+use color_eyre::eyre::Context;
 use kxio::net::{Net, ReqBuilder};
 
 use crate::trello::model::{TrelloAttachment, TrelloAttachmentId};
@@ -26,6 +28,14 @@ impl<'ctx> TrelloClient<'ctx> {
         f!("https://api.trello.com/1{path}")
     }
 
+    fn auth_headers(&self) -> HashMap<String, String> {
+        let api_key = &self.ctx.cfg.trello.api_key;
+        let api_secret = &self.ctx.cfg.trello.api_secret;
+        HashMap::from([(
+            s!("Authorization"),
+            f!(r#"OAuth oauth_consumer_key="{api_key}", oauth_token="{api_secret}""#,),
+        )])
+    }
     fn common_headers(&self) -> HashMap<String, String> {
         let api_key = &self.ctx.cfg.trello.api_key;
         let api_secret = &self.ctx.cfg.trello.api_secret;
@@ -53,6 +63,34 @@ impl<'ctx> TrelloClient<'ctx> {
         )
         .await
     }
+
+    pub(crate) async fn save_attachment(
+        &self,
+        card_id: &TrelloCardId,
+        attachment_id: &TrelloAttachmentId,
+        file_name: Option<std::path::PathBuf>,
+    ) -> color_eyre::Result<PathBuf> {
+        let attachment = self.card_attachment(card_id, attachment_id).await.result?;
+        let url = attachment.url;
+        let file_name = file_name.unwrap_or_else(|| attachment.file_name.into());
+        crate::e!(self.ctx.prt, "file_name: {}", file_name.display());
+        crate::e!(self.ctx.prt, "base: {}", self.ctx.fs.base().display());
+        let file_name = self.ctx.fs.base().join(file_name);
+        crate::e!(self.ctx.prt, "file_name: {}", file_name.display());
+        let resp = self
+            .ctx
+            .net
+            .get(url)
+            .headers(self.auth_headers())
+            .header("accept", "application/octet")
+            .send()
+            .await?
+            .bytes()
+            .await?;
+        let file = self.ctx.fs.file(&file_name);
+        file.write(resp).context("writing to disk")?;
+        Ok(file_name)
+    }
 }
 
 impl<'ctx> TrelloClient<'ctx> {
diff --git a/src/trello/tests.rs b/src/trello/tests.rs
index 9c95ce0..f80bf49 100644
--- a/src/trello/tests.rs
+++ b/src/trello/tests.rs
@@ -75,8 +75,8 @@ mod commands {
             .body(include_str!("../tests/responses/trello-board-get.json"))
             .expect("mock request");
 
-        // let fs = given::a_filesystem();
-        let ctx = given::a_full_context(mock_net);
+        let fs = given::a_filesystem();
+        let ctx = given::a_full_context(mock_net, fs);
 
         //when
         let result = ctx
@@ -123,8 +123,8 @@ mod commands {
 
             prep_mock_get(&mock_net);
 
-            // let fs = given::a_filesystem();
-            let ctx = given::a_full_context(mock_net);
+            let fs = given::a_filesystem();
+            let ctx = given::a_full_context(mock_net, fs);
             let prt = ctx.prt.clone();
             let prt = prt.as_test().unwrap();
             let command = Command::Trello(TrelloCommand::Card(TrelloCardCommand::Get {
@@ -147,8 +147,8 @@ mod commands {
 
             prep_mock_get(&mock_net);
 
-            // let fs = given::a_filesystem();
-            let ctx = given::a_full_context(mock_net);
+            let fs = given::a_filesystem();
+            let ctx = given::a_full_context(mock_net, fs);
             let prt = ctx.prt.clone();
             let prt = prt.as_test().unwrap();
             let command = Command::Trello(TrelloCommand::Card(TrelloCardCommand::Get {
@@ -195,8 +195,8 @@ mod commands {
 
                 prep_mock_get(&mock_net);
 
-                // let fs = given::a_filesystem();
-                let ctx = given::a_full_context(mock_net);
+                let fs = given::a_filesystem();
+                let ctx = given::a_full_context(mock_net, fs);
                 let prt = ctx.prt.clone();
                 let prt = prt.as_test().unwrap();
                 let command =
@@ -207,7 +207,7 @@ mod commands {
                     }));
 
                 //when
-                command.execute(ctx).await;
+                command.execute(ctx).await.expect("execute");
 
                 //then
                 let output = prt.output();
@@ -221,8 +221,8 @@ mod commands {
 
                 prep_mock_get(&mock_net);
 
-                // let fs = given::a_filesystem();
-                let ctx = given::a_full_context(mock_net);
+                let fs = given::a_filesystem();
+                let ctx = given::a_full_context(mock_net, fs);
                 let prt = ctx.prt.clone();
                 let prt = prt.as_test().unwrap();
                 let command =
@@ -233,7 +233,7 @@ mod commands {
                     }));
 
                 //when
-                command.execute(ctx).await;
+                command.execute(ctx).await.expect("execute");
 
                 //then
                 let output = prt.output();
@@ -255,6 +255,85 @@ mod commands {
                     .expect("mock request");
             }
         }
+
+        mod save {
+            use super::*;
+            use bytes::Bytes;
+
+            #[tokio::test]
+            async fn save_writes_file() {
+                //given
+                let mock_net = kxio::net::mock();
+
+                prep_mock_get(&mock_net);
+
+                let fs = given::a_filesystem();
+                let test_fs = fs.clone();
+                let ctx = given::a_full_context(mock_net, fs);
+                let command =
+                    Command::Trello(TrelloCommand::Attachment(TrelloAttachmentCommand::Save {
+                        card_id: s!("65ad94865aed24f70ecdcebb"),
+                        attachment_id: s!("65ad94875aed24f70ecdd037"),
+                        file_name: None,
+                    }));
+
+                //when
+                command.execute(ctx).await.expect("execute");
+
+                //then
+                let file = test_fs.base().join("Backlog.png");
+                assert!(file.exists());
+            }
+
+            #[tokio::test]
+            async fn save_log_output() {
+                //given
+                let mock_net = kxio::net::mock();
+
+                prep_mock_get(&mock_net);
+
+                let fs = given::a_filesystem();
+                let test_fs = fs.clone();
+                let ctx = given::a_full_context(mock_net, fs);
+                let prt = ctx.prt.clone();
+                let prt = prt.as_test().unwrap();
+                let command =
+                    Command::Trello(TrelloCommand::Attachment(TrelloAttachmentCommand::Save {
+                        card_id: s!("65ad94865aed24f70ecdcebb"),
+                        attachment_id: s!("65ad94875aed24f70ecdd037"),
+                        file_name: None,
+                    }));
+
+                //when
+                command.execute(ctx).await.expect("execute");
+
+                //then
+                let file = test_fs.base().join("Backlog.png");
+                drop(test_fs);
+                let output = prt.output();
+                assert_eq!(output.trim(), crate::f!("Wrote: {}", file.display()));
+            }
+
+            fn prep_mock_get(mock_net: &MockNet) {
+                mock_net
+                    .on()
+                    .get("https://api.trello.com/1/cards/65ad94865aed24f70ecdcebb/attachments/65ad94875aed24f70ecdd037")
+                    .header("authorization", "OAuth oauth_consumer_key=\"trello-api-key\", oauth_token=\"trello-api-secret\"")
+                    .header("accept", "application/json")
+                    .header("content-type", "application/json")
+                    .respond(StatusCode::OK)
+                    .body(include_str!("../tests/responses/trello-attachment-get.json"))
+                    .expect("mock request 1");
+
+                mock_net
+                    .on()
+                    .get("https://trello.com/1/cards/65ad94865aed24f70ecdcebb/attachments/65ad94875aed24f70ecdd037/download/Backlog.png")
+                    .header("authorization", "OAuth oauth_consumer_key=\"trello-api-key\", oauth_token=\"trello-api-secret\"")
+                    .respond(StatusCode::OK)
+                    .body(Bytes::from(include_bytes!("../tests/responses/trello-attachment-save.png").as_slice()))
+                    .expect("mock request 2");
+            }
+        }
     }
 }