Change all occurrences of file_name to filename (#4059)

pages/linux/dpkg.md

@@ -24,4 +24,4 @@
 
 - Find out which package owns a file:
 
-`dpkg -S {{file_name}}`
+`dpkg -S {{filename}}`

pages/linux/toilet.md

@@ -9,7 +9,7 @@
 
 - Generate ASCII art using a custom font file:
 
-`toilet {{input_text}} -f {{font_file_name}}`
+`toilet {{input_text}} -f {{font_filename}}`
 
 - Generate ASCII art using a filter:
 

pages/linux/tshark.md

@@ -32,4 +32,4 @@
 
 - Analyze packets from a file:
 
-`tshark -r {{file_name}}.pcap`
+`tshark -r {{filename}}.pcap`

pages/linux/uvcdynctrl.md

@@ -24,8 +24,8 @@
 
 - Save the state of the current controls to a file:
 
-`uvcdynctrl -W {{file_name}}`
+`uvcdynctrl -W {{filename}}`
 
 - Load the state of the controls from a file:
 
-`uvcdynctrl -L {{file_name}}`
+`uvcdynctrl -L {{filename}}`