Practical Methods to Open Files from the Linux Command Line

File access is central to Linux administration—reading logs, editing configuration files, or opening data for pipelines. Although graphical file explorers exist, the majority of production workloads and most DevOps tasks occur over SSH, with only the shell available.

Below is a practical reference to essential methods for opening, viewing, and editing files directly from the command line. Tested on Ubuntu 22.04 LTS, but these patterns apply across most major distributions.

Viewing Files: Fast Inspection vs. Large Output Navigation

Sometimes, all you need is a quick glance at a log or config. Other times, the file size demands efficient navigation.

cat: Simple Dump

Prints the entire file to STDOUT. Best for small files.

cat /etc/hostname

Problem: With multi-megabyte files (/var/log/syslog, application logs from Java apps), terminal scrollback overflows and you may miss critical sections.

less: Interactive Pager

Opens the file in a navigable interface. Arrow keys, / for search, q to quit. Handles MBs of data without clogging your shell.

less /var/log/syslog

Known issue: Over SSH, if your $TERM is set incorrectly, less may fail with messages like WARNING: terminal is not fully functional. Reset with export TERM=xterm.

more: Legacy Pager

more comes before less. Lacks backward navigation and advanced search. Fine on minimal installs:

more /etc/passwd

Editing Files In-Terminal

Editing config without root cause analysis often leads to errors. Always make a backup.

nano: Accessible Editor

Available by default on most distros. UI at the bottom for saving/quitting, e.g., Ctrl+O (write), Ctrl+X (exit).

nano /etc/hosts

Note: Fails silently if file is unwritable—use sudo nano /etc/hosts for privileged files.

vim / vi: Power at a Cost

Full-featured, steep learning curve. For quick edits post-incident, vi will work with minimal dependencies.

vim /etc/fstab

• i to insert
• :wq to save and exit
• :q! to quit discarding changes

Mismatch in vim versions leads to subtle issues (syntax highlighting missing, clipboard not functional). Confirm with vim --version.

Opening Files with GUI Applications

Relevant only within a desktop session (non-SSH, non-headless). Can launch GUI programs directly from terminal, returning control with &.

Using xdg-open

Platform-neutral. Launches the file with its default handler.

xdg-open ~/Documents/design.pdf &

Observed: On Wayland desktops, may need additional handlers installed, or xdg-open reports No application is registered as handling this file.

Explicit Application Invocation

Directly call application binary where needed:

eog image.png &
gimp artwork.xcf &

Gotcha: Running with & detaches from current terminal; without it, shell blocks.

Summary Table

Additional Tactics

• Tab-complete paths and filenames to avoid typing errors.

• To view inside compressed files:

  zless /var/log/auth.log.1.gz
  

• For files requiring elevated privileges, prefix with sudo.

• Pipes for real-world triage:

  cat /var/log/syslog | grep -i error | less
  

Practical note: tail -f /path/to/log is invaluable during troubleshooting of long-running services. Use less +F for similar paged, follow-style viewing.

Closing Notes

Command-line file access isn’t just a rite of passage—it’s essential for deployment automation, rapid debugging, and audit trails. Familiarity with these tools saves considerable time, particularly in incident response or CI/CD pipelines. Where possible, master both less and vim (or your preferred editor)—they’re available nearly everywhere, and robust against most real-world scenarios.

If you're looking for deeper scripting, integrating file opens into automated workflows, or even file descriptor manipulation, consider advanced tools—awk, sed, and shell redirection patterns. Those fall outside this initial reference.

Known issue: Some corporate lockdowns restrict editor binaries or custom shell environments. Always check $PATH for expected tools during onboarding.