diff --git a/README.md b/README.md
index 617ff12..8c02b37 100644
--- a/README.md
+++ b/README.md
@@ -90,6 +90,30 @@ Submit a job that needs 8 CPUs
 $ ssubmit -m 16g -t 1d align "minimap2 -t 8 ref.fa query.fq > out.paf" -- -c 8
 ```
 
+```
+$ ssubmit -h
+Submit sbatch jobs without having to create a submission script
+
+Usage: ssubmit [OPTIONS] <NAME> <COMMAND> [-- <REMAINDER>...]
+
+Arguments:
+  <NAME>          Name of the job
+  <COMMAND>       Command to be executed by the job
+  [REMAINDER]...  Options to be passed on to sbatch
+
+Options:
+  -o, --output <OUTPUT>    File to write job stdout to. (See `man sbatch | grep -A 3 'output='`) [default: %x.out]
+  -e, --error <ERROR>      File to write job stderr to. (See `man sbatch | grep -A 3 'error='`) [default: %x.err]
+  -m, --mem <size[unit]>   Specify the real memory required per node. e.g., 4.3kb, 7 Gb, 9000, 4.1MB become 5KB, 7000M, 9000M, and 5M, respectively [env: SSUBMIT_MEMORY=] [default: 1G]
+  -t, --time <TIME>        Time limit for the job. e.g. 5d, 10h, 45m21s (case-insensitive) [env: SSUBMIT_TIME=] [default: 1d]
+  -S, --shebang <SHEBANG>  The shell shebang for the submission script [env: SSUBMIT_SHEBANG=] [default: "#!/usr/bin/env bash"]
+  -s, --set <SET>          Options for the set command in the shell script [env: SSUBMIT_SET=] [default: "euxo pipefail"]
+  -n, --dry-run            Print the sbatch command and submission script that would be executed, but do not execute them
+  -T, --test-only          Return an estimate of when the job would be scheduled to run given the current queue. No job is actually submitted. [sbatch --test-only]
+  -h, --help               Print help (see more with '--help')
+  -V, --version            Print version
+```
+
 The basic anatomy of a `ssubmit` call is
 
 ```
@@ -114,6 +138,8 @@ For example, 1.1M will be rounded up to 2M. If you want to use the default memor
 
 For simplicity's sake, all values over one megabyte are passed to sbatch as megabytes - e.g., 1.1G will be passed as 1100M.
 
+The environment variable `SSUBMIT_MEM` can be set to a default memory limit. This can be overridden by passing `-m`.
+
 ### Time
 
 As with memory, time (`-t,--time`) is intended to be simple. If you want a time limit of
@@ -124,6 +150,8 @@ a full list of supported time units, check out the
 [`duration-str`](https://github.com/baoyachi/duration-str) repo. One thing to note is that passing a single digit, without a unit, will be interpreted by 
 slurm as minutes. However, not providing a unit in the example of `5m3` will be interpreted as 5 minutes and 3 seconds.
 
+The environment variable `SSUBMIT_TIME` can be set to a default time limit. This can be overridden by passing `-t`.
+
 ### Dry run
 
 You can see what `ssubmit` would do without actually submitting a job using dry run
@@ -137,7 +165,7 @@ sbatch -c 8 <script>
 =====<script>=====
 #!/usr/bin/env bash
 #SBATCH --job-name=dry
-#SBATCH --mem=4G
+#SBATCH --mem=4000M
 #SBATCH --time=24:0:0
 #SBATCH --error=%x.err
 #SBATCH --output=%x.out
@@ -150,12 +178,12 @@ rsync -az src/ dest/
 ### Script settings
 
 The default shebang for the script is `#!/usr/bin/env bash`. However, if you'd prefer
-something else, pass this with `-S,--shebang`.
+something else, pass this with `-S,--shebang` or set the environment variable `SSUBMIT_SHEBANG`.
 
 Additionally, we use `set -euxo pipefail` by default, which will exit when a command exits with a
 non-zero exit code (`e`), error when trying to use an unset variable (`u`), print
 all commands that were run to stderr (`x`), and exit if a command in a pipeline fails 
-(`-o pipefail`). You can change these setting with `-s,--set`. You can turn this off 
+(`-o pipefail`). You can change these setting with `-s,--set` or the environment variable `SSUBMIT_SET`. You can turn this off 
 by passing `-s ''`.
 
 ### Log files
@@ -168,7 +196,7 @@ You don't have to use patterns of course.
 
 ### Full usage
 
-```shell
+```
 $ ssubmit --help
 ssubmit 0.2.0
 Michael Hall <michael@mbh.sh>
@@ -185,80 +213,92 @@ $ ssubmit -m 600m rsync_my_data "rsync -az src/ dest/"
 Submit a command that involves piping the output into another command. sbatch options
 are passed after a `--`.
 
+$ ssubmit -m 4G align "minimap2 -t 8 ref.fa reads.fq | samtools sort -o sorted.bam" -- -c 8
+Submit sbatch jobs without having to create a submission script
+
+-----------
+# EXAMPLES
+-----------
+
+Submit a simple rsync command with a 600MB memory limit.
+
+$ ssubmit -m 600m rsync_my_data "rsync -az src/ dest/"
+
+Submit a command that involves piping the output into another command. sbatch options
+are passed after a `--`.
+
 $ ssubmit -m 4G align "minimap2 -t 8 ref.fa reads.fq | samtools sort -o sorted.bam" -- -c 8
 
-USAGE:
-    ssubmit [OPTIONS] <NAME> <COMMAND> [-- <REMAINDER>...]
+Usage: ssubmit [OPTIONS] <NAME> <COMMAND> [-- <REMAINDER>...]
 
-ARGS:
-    <NAME>
-            Name of the job
+Arguments:
+  <NAME>
+          Name of the job
 
-            See `man sbatch | grep -A 2 'job-name='` for more details.
+          See `man sbatch | grep -A 2 'job-name='` for more details.
 
-    <COMMAND>
-            Command to be executed by the job
+  <COMMAND>
+          Command to be executed by the job
 
-    <REMAINDER>...
-            Options to be passed on to sbatch
+  [REMAINDER]...
+          Options to be passed on to sbatch
 
-OPTIONS:
-    -e, --error <ERROR>
-            File to write job stderr to. (See `man sbatch | grep -A 3 'error='`)
+Options:
+  -o, --output <OUTPUT>
+          File to write job stdout to. (See `man sbatch | grep -A 3 'output='`)
 
-            Run `man sbatch | grep -A 37 '^filename pattern'` to see available patterns.
+          Run `man sbatch | grep -A 37 '^filename pattern'` to see available patterns.
 
-            [default: %x.err]
+          [default: %x.out]
 
-    -h, --help
-            Print help information
+  -e, --error <ERROR>
+          File to write job stderr to. (See `man sbatch | grep -A 3 'error='`)
 
-    -m, --mem <size[units]>
-            Specify the real memory required per node. e.g., 4.3kb, 7G, 9000, 4.1MB
+          Run `man sbatch | grep -A 37 '^filename pattern'` to see available patterns.
 
-            Note, floating point numbers will be rounded up. e.g., 10.1G will request 11G. This is
-            because sbatch only allows integers. See `man sbatch | grep -A 4 'mem='` for the full
-            details.
+          [default: %x.err]
 
-            [default: 1G]
+  -m, --mem <size[unit]>
+          Specify the real memory required per node. e.g., 4.3kb, 7 Gb, 9000, 4.1MB become 5KB, 7000M, 9000M, and 5M, respectively.
 
-    -n, --dry-run
-            Print the sbatch command and submission script would be executed, but do not execute
-            them
+          If no unit is specified, megabytes will be used, as per the sbatch default. The value will be rounded up to the nearest megabyte. If the value is less than 1M, it will be rounded up to the nearest kilobyte. See `man sbatch | grep -A 4 'mem='` for the full details.
 
-    -o, --output <OUTPUT>
-            File to write job stdout to. (See `man sbatch | grep -A 3 'output='`)
+          [env: SSUBMIT_MEMORY=]
+          [default: 1G]
 
-            Run `man sbatch | grep -A 37 '^filename pattern'` to see available patterns.
+  -t, --time <TIME>
+          Time limit for the job. e.g. 5d, 10h, 45m21s (case-insensitive)
 
-            [default: %x.out]
+          Run `man sbatch | grep -A 7 'time=<'` for more details. If a single digit is passed, it will be passed straight to sbatch (i.e. minutes). However, 5m5 will be considered 5 minutes and 5 seconds.
 
-    -s, --set <SET>
-            Options for the set command in the shell script
+          [env: SSUBMIT_TIME=]
+          [default: 1d]
 
-            For example, to exit when the command exits with a non-zero code and to treat unset
-            variables as an error during substitution, pass 'eu'. Pass '' or "" to set nothing
+  -S, --shebang <SHEBANG>
+          The shell shebang for the submission script
 
-            [default: "euxo pipefail"]
+          [env: SSUBMIT_SHEBANG=]
+          [default: "#!/usr/bin/env bash"]
 
-    -S, --shebang <SHEBANG>
-            The shell shebang for the submission script
+  -s, --set <SET>
+          Options for the set command in the shell script
 
-            [default: "#!/usr/bin/env bash"]
+          For example, to exit when the command exits with a non-zero code and to treat unset variables as an error during substitution, pass 'eu'. Pass '' or "" to set nothing
 
-    -t, --time <TIME>
-            Time limit for the job. e.g. 5d, 10h, 45m21s (case insensitive)
+          [env: SSUBMIT_SET=]
+          [default: "euxo pipefail"]
 
-            Run `man sbatch | grep -A 7 'time=<'` for more details.
+  -n, --dry-run
+          Print the sbatch command and submission script that would be executed, but do not execute them
 
-            [default: 1w]
+  -T, --test-only
+          Return an estimate of when the job would be scheduled to run given the current queue. No job is actually submitted. [sbatch --test-only]
 
-    -T, --test-only
-            Return an estimate of when the job would be scheduled to run given the current queue. No
-            job is actually submitted. [sbatch --test-only]
+  -h, --help
+          Print help (see a summary with '-h')
 
-    -V, --version
-            Print version information
+  -V, --version
+          Print version
 ```
 
 
diff --git a/src/cli.rs b/src/cli.rs
index 88e0a21..ce82eab 100644
--- a/src/cli.rs
+++ b/src/cli.rs
@@ -4,6 +4,11 @@ use regex::Regex;
 
 use ssubmit::SlurmTime;
 
+const SSUBMIT_SHEBANG: &str = "SSUBMIT_SHEBANG";
+const SSUBMIT_MEMORY: &str = "SSUBMIT_MEMORY";
+const SSUUBMIT_TIME: &str = "SSUBMIT_TIME";
+const SSUBMIT_SET: &str = "SSUBMIT_SET";
+
 /// Submit sbatch jobs without having to create a submission script
 ///
 /// -----------
@@ -47,17 +52,17 @@ pub struct Cli {
     /// be rounded up to the nearest megabyte. If the value is less than 1M, it will be rounded up
     /// to the nearest kilobyte.
     /// See `man sbatch | grep -A 4 'mem='` for the full details.
-    #[arg(short, long = "mem", value_name = "size[unit]", default_value = "1G", value_parser = parse_memory)]
+    #[arg(short, long = "mem", value_name = "size[unit]", default_value = "1G", value_parser = parse_memory, env = SSUBMIT_MEMORY)]
     pub memory: String,
     /// Time limit for the job. e.g. 5d, 10h, 45m21s (case-insensitive)
     ///
     /// Run `man sbatch | grep -A 7 'time=<'` for more details. If a single digit is passed, it will
     /// be passed straight to sbatch (i.e. minutes). However, 5m5 will be considered 5 minutes and
     /// 5 seconds.
-    #[arg(short, long, value_parser = parse_time, default_value = "1w")]
+    #[arg(short, long, value_parser = parse_time, default_value = "1d", env = SSUUBMIT_TIME)]
     pub time: String,
     /// The shell shebang for the submission script
-    #[arg(short = 'S', long, default_value = "#!/usr/bin/env bash")]
+    #[arg(short = 'S', long, default_value = "#!/usr/bin/env bash", env = SSUBMIT_SHEBANG)]
     pub shebang: String,
     /// Options for the set command in the shell script
     ///
@@ -67,10 +72,11 @@ pub struct Cli {
         short,
         long,
         default_value = "euxo pipefail",
-        allow_hyphen_values = true
+        allow_hyphen_values = true,
+        env = SSUBMIT_SET
     )]
     pub set: String,
-    /// Print the sbatch command and submission script would be executed, but do not execute them
+    /// Print the sbatch command and submission script that would be executed, but do not execute them
     #[arg(short = 'n', long)]
     pub dry_run: bool,
     /// Return an estimate of when the job would be scheduled to run given the current
@@ -460,4 +466,69 @@ mod tests {
         let expected = "0";
         assert_eq!(actual, expected);
     }
+
+    #[test]
+    fn test_cli_parse_remainder() {
+        let args = Cli::parse_from(["ssubmit", "name", "command", "--", "-c", "8"]);
+
+        let actual = args.remainder.join(" ");
+        let expected = "-c 8";
+        assert_eq!(actual, expected);
+    }
+
+    #[test]
+    fn test_cli_parse_set_shebang_with_environment_variable() {
+        let shebang = "#!/bin/zsh";
+        unsafe {
+            std::env::set_var(SSUBMIT_SHEBANG, shebang);
+        }
+
+        let args = Cli::parse_from(["ssubmit", "name", "command"]);
+
+        let actual = args.shebang;
+        let expected = shebang;
+        assert_eq!(actual, expected);
+    }
+
+    #[test]
+    fn test_cli_parse_set_memory_with_environment_variable() {
+        let memory = "4M";
+        unsafe {
+            std::env::set_var(SSUBMIT_MEMORY, memory);
+        }
+
+        let args = Cli::parse_from(["ssubmit", "name", "command"]);
+
+        let actual = args.memory;
+        let expected = memory;
+        assert_eq!(actual, expected);
+    }
+
+    #[test]
+    fn test_cli_parse_set_time_with_environment_variable() {
+        let time = "1:0";
+        unsafe {
+            std::env::set_var(SSUUBMIT_TIME, time);
+        }
+
+        let args = Cli::parse_from(["ssubmit", "name", "command"]);
+
+        let actual = args.time;
+        let expected = time;
+        assert_eq!(actual, expected);
+    }
+
+    #[test]
+    fn test_cli_parse_set_with_environment_variable() {
+        let set = "eu";
+        unsafe {
+            std::env::set_var(SSUBMIT_SET, set);
+        }
+
+        let args = Cli::parse_from(["ssubmit", "name", "command"]);
+
+        let actual = args.set;
+        let expected = set;
+        assert_eq!(actual, expected);
+    }
 }