CODEWITHSUNDEEP
linuxbashshell
FreelancePoliceman
FreelancePoliceman

Reputation: 11

Executing different commands with separate arguments

Say that I want to make a script that extracts all tar.gz and tar.bz2 files that are listed as arguments. What I've done so far is something like: 

if [[ $@ =~ .*"tar.gz".* ]] || [[ $@ =~ .*"tar.bz2".* ]]; then
 for i in $@ =~ .*"tar.gz".*; do
  tar -xvzf "$i"
 done
 for p in $@ =~ .*"tar.bz2".*; do
  tar -xvjf "$p"
 done
else
 echo "tar.gz or tar.bz2 files required."
fi

The first line is successful at evaluating whether or not a tar.gz or tar.bz2 file exist, but my problem is the rest. The variables aren't set properly, and the script ends up trying to extract each variable listed with both extraction commands. How can I separate arguments that end with tar.gz and tar.bz2 to perform separate extractions?

Upvotes: 0

Views: 89

Answers (3)

Fred
Fred

Reputation: 6995

You should probably iterate over arguments and test each argument, like this :

#!/bin/bash

declare -i count
for file in "$@"
do
  if
    [[ $file =~ .*[.]tar[.]gz$ ]]
  then
    tar -xvzf "$file"
  elif
    [[ $file =~ .*[.]tar[.]bz2$ ]]
  then
    tar -xvjf "$file"
  else
    continue
  fi
  count+=1
fi 

((count)) || echo "tar.gz or tar.bz2 files required."

If you are OK to rely on GNU tar choosing the right decoding algorithm automatically, you can simplify this to :

#!/bin/bash

declare -i count
for file in "$@"
do
  [[ $file =~ .*[.]tar[.](gz|bz2)$ ]] || continue
  tar -xvf "$file"
  count+=1
fi 

((count)) || echo "tar.gz or tar.bz2 files required."

Upvotes: 3

Maxim Egorushkin
Maxim Egorushkin

Reputation: 136246

A bit off-topic, when extracting with GNU tar it detects the archive type automatically from the file extension since 2007, no need to specify z|j|J.

I.e. tar xvf <filename>.

Upvotes: 0

Charles Duffy
Charles Duffy

Reputation: 295373

There isn't any built-in syntax for extracting and iterating over only matching elements of an array, as you're trying to do here.

The below is POSIX-compliant, depending on no bashisms:

count=0
for arg; do
  case $arg in
    *.tar.gz)  tar -xvzf "$arg"; count=$(( count + 1 ));;
    *.tar.bz2) tar -xjvf "$arg"; count=$(( count + 1 ));;
  esac
done
if [ "$count" -eq 0 ]; then
  echo "tar.gz or tar.bz2 files required" >&2
fi

Upvotes: 3

Related Questions