Linux - File

1 - About

Linux file management

3 - Basic

4 - Type

4.1 - hidden

A full stop '.' before the name of the file makes it a hidden file. Example '.bash'

Sh - Hidden files

4.2 - Metadata

5 - Management

5.1 - Get

5.1.1 - Filename and extension

Using Parameters Expansion Removal

fileFullName=$(basename "$filePath")
# or

5.1.2 - parent directory

  • From a path string where the file does not exist

echo ${VAR%/*}


  • dirname returns the first parent of an existing path file.

dirname "dir/file"


5.1.3 - File Permission

5.1.4 - File exist

if [ ! -f $PATH ]; then
    echo "File $PATH not found!"

5.1.5 - Absolute path

ABSOLUTE_PATH=$(realpath "${FILE_NAME}")

5.1.6 - Size

with Linux - ls (List directory content)

ls -lh myFile | awk '{ print $5 }'


  • -lh shows a human readable size
  • an awk will extract the 5de column of the ls output

5.2 - Monitoring the size of a (log) file


# the program that run
# the log of the progam
# Don't touch below, the program
while kill -0 $(pgrep ${program}) 2> /dev/null; do
    count=$(( $count + 1 ))
	size=$(ls -lh ${logfile} | awk '{ print $5 }')
    echo "${count} - Process is running and the log is ${size}"
    sleep 10
echo "${count} - Process has exited"

5.3 - Comparison

cmp --silent $old $new || echo "files are different"
cmp -b $old $new 

See also : diff

5.4 - Diff

diff file1 file2 | cat -t


  • ^M for CR,
  • ^I for tab

See also: comparison

5.5 - Filter a list of files ?

This command below gives you all files in the current directory which begin by elfutils

dir | grep -i elfutils


  • find can do it recursviely

5.6 - Remove a file?

Permission: In UNIX and Linux, the ability to remove a file is determined by the access bits of parent directory

chmod 777 .
chown hi-adm:hi-adm .

With the command rm


  • Basic

rm filename.extension

  • Prompts for confirmation before removing a file

rm -i filename.extension

  • Force removal of the file regardless of it bieng write-protected or open

rm -f filename.extension
  • Remove files recursively in 'directory'

rm -r directory

More … perform the man commando

man rm

5.7 - Copy 1 or multiple file

cp - Copy one or more files to another location.


  • Copy of a directory with resistivity:

cp -r dirtocopy newdir

  • Copy two files

cp myFile1.txt myFile2.txt myDirDestination

  • Copy all files of directory

cp * myDirDestination
# or
cp /myDirSource/* /myDirDestination

  • Copy all txt files (with a pattern)

cp *.txt myDirDestination

5.8 - Move / Rename

  • mv - Moves or renames file


mv file.log file.$(date "+%Y.%m.%d-%H.%M.%S").log

5.9 - Concatenate

cat file1 file2 > finalFile

# example with cert
cat first_cert.pem second_cert.pem > combined_cert.pem

5.10 - Transfer

5.11 - See the content

5.12 - Search a file by name

  • locate - List files that match a pattern.

Locate all file with a regular expression. In this example all file which begin with sp and end up with the extension msb.

locate -r "sp.*\.msb"

  • find - search for files in a directory hierarchy.

find /my/directory -name myFile.extension

5.13 - Search files based on time

touch -d '2011-12-31 10:22' foo
find . -newer foo

See all other files in the time section of the find command

5.14 - Search the content of files

5.15 - File Architecture (32 or 64 bit)

File Architecture

file fileName


file java

/bin/java: ELF 64-bit LSB executable, AMD x86-64, version 1 (SYSV), for GNU/Linux 2.6.9, dynamically linked (uses shared libs), for GNU/Linux 2.6.9, not stripped

5.16 - Iterate

OLDIFS=$IFS; IFS=$'\n'; 
filelines=`cat $filename`
for line in $filelines ; do
    echo $line

5.17 - Security / Capabilty

See setcap - set file capabilities.

A file may also be an executable one and they may got capabilities such as be able to take the port 80

5.18 - Processing

6 - List of command

  • ls - List contents of a directory
  • which - Displays path to command
  • whereis - locate the binary, source, and manual page files for a command

7 - Content

Data Science
Data Analysis
Data Science
Linear Algebra Mathematics

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