Mastering scp: Essential Commands, Options, and Real‑World Examples

Basic Syntax

The basic scp command copies a file from the local host to a remote host using the format:

scp source_file_name username@destination_host:destination_folder

Verbose Output (-v)

Adding -v prints detailed debugging information, which helps diagnose connection, authentication, and configuration problems.

rumenz@local $ scp -v Label.pdf [email protected]:.
Executing: program /usr/bin/ssh host 192.168.1.110, user rumenz, command scp -v -t .
OpenSSH_6.0p1 Debian-3, OpenSSL 1.0.1c 10 May 2012
... (debug output) ...
Label.pdf 100% 3672KB 136.0KB/s 00:27

Preserve Timestamps and Modes (-p)

The -p flag preserves the original file’s modification time, access time, and mode.

rumenz@local $ scp -p Label.pdf [email protected]:.
Label.pdf 100% 3672KB 126.6KB/s 00:29

Enable Compression (-C)

Using -C compresses data during transfer, which can speed up copying large files over the network. Compression is performed only on the wire; the file is restored to its original size on the destination.

rumenz@local $ scp -Cpv messages.log [email protected]:.
... (debug output) ...
messages.log 100% 93MB 602.7KB/s 02:38
debug1: compress outgoing: raw data 97571111, compressed 8806191, factor 0.09

Change Encryption Cipher (-c)

By default scp uses AES‑128. To use a different cipher, such as 3DES, specify the -c option.

rumenz@local $ scp -c 3des Label.pdf [email protected]:.
Label.pdf 100% 3672KB 282.5KB/s 00:13

Limit Bandwidth (-l)

The -l option limits bandwidth usage in kilobytes per second. For example, to cap the transfer at roughly 50 KB/s, set -l 400 (since scp’s unit is KB/s and 1 KB = 8 Kb).

rumenz@local $ scp -l 400 Label.pdf [email protected]:.
Label.pdf 100% 3672KB 50.3KB/s 01:13

Specify a Non‑Standard Port (-P)

scp uses port 22 by default. To connect to a different SSH port, use -P followed by the port number.

rumenz@local $ scp -P 2249 Label.pdf [email protected]:.
Label.pdf 100% 3672KB 262.3KB/s 00:14

Recursive Copy (-r)

To copy an entire directory and its contents, add the -r flag.

rumenz@local $ scp -r documents [email protected]:.
... (transfer output) ...
scp.txt 100% 10KB 9.8KB/s 00:00

After completion, a documents directory containing all files appears on the remote host.

Suppress Progress and Messages (-q)

The -q option disables progress meters and diagnostic messages, leaving only the password prompt and the final shell prompt.

rumenz@local $ scp -q Label.pdf [email protected]:.
... (no progress output) ...
rumenz@local $

Using a Proxy

When a network requires a proxy, scp itself cannot be configured directly. Instead, create an ~/.ssh/config entry that uses ProxyCommand with a tool like corkscrew:

ProxyCommand /usr/bin/corkscrew 10.0.96.6 8080 %h %p ~/.ssh/proxyauth

Store the proxy credentials in ~/.ssh/proxyauth (format username:password) and ensure the file is readable only by the user.

Install corkscrew with:

# apt-get install corkscrew   # Debian/Ubuntu
# yum install corkscrew       # CentOS

Selecting a Different ssh_config File (-F)

For users who frequently switch between corporate and public networks, maintain separate ssh configuration files and specify which one to use with -F: scp -F /home/pungki/proxy_ssh_config Label.pdf The default configuration resides in ~/.ssh/config. Using -F allows quick switching without editing the default file each time.

Additional Tips

Compression ( -C) is ineffective on already compressed files such as .zip, .rar, images, or .iso.

Bandwidth limits are expressed in kilobytes per second; calculate the desired limit accordingly.

Combine options as needed (e.g., scp -Cpv for compressed, verbose, and preserving timestamps).