How to read first four characters of file name?

I have several files whose extensions are .gz with similar filenames to:

ANKR00TUR_R_20183350000_01D_30S_MO.crx.gz

I need to read the first four characters of these files' names and store these characters in a file. How can I do this?

edited Jan 7 at 12:31

Arronical

13.2k84791

asked Jan 7 at 12:02

deepblue_86

5851023

The first 4 bytes of the compressed file or of the uncompressed file?

– PerlDuck
Jan 7 at 12:04

compressed file

– deepblue_86
Jan 7 at 12:05

add a comment |

I have several files whose extensions are .gz with similar filenames to:

ANKR00TUR_R_20183350000_01D_30S_MO.crx.gz

I need to read the first four characters of these files' names and store these characters in a file. How can I do this?

edited Jan 7 at 12:31

Arronical

13.2k84791

asked Jan 7 at 12:02

deepblue_86

5851023

The first 4 bytes of the compressed file or of the uncompressed file?

– PerlDuck
Jan 7 at 12:04

compressed file

– deepblue_86
Jan 7 at 12:05

add a comment |

I have several files whose extensions are .gz with similar filenames to:

ANKR00TUR_R_20183350000_01D_30S_MO.crx.gz

I need to read the first four characters of these files' names and store these characters in a file. How can I do this?

edited Jan 7 at 12:31

Arronical

13.2k84791

asked Jan 7 at 12:02

deepblue_86

5851023

I have several files whose extensions are .gz with similar filenames to:

ANKR00TUR_R_20183350000_01D_30S_MO.crx.gz

I need to read the first four characters of these files' names and store these characters in a file. How can I do this?

scripts

edited Jan 7 at 12:31

Arronical

13.2k84791

asked Jan 7 at 12:02

deepblue_86

5851023

edited Jan 7 at 12:31

Arronical

13.2k84791

asked Jan 7 at 12:02

deepblue_86

5851023

edited Jan 7 at 12:31

Arronical

13.2k84791

edited Jan 7 at 12:31

Arronical

13.2k84791

edited Jan 7 at 12:31

Arronical

13.2k84791

asked Jan 7 at 12:02

deepblue_86

5851023

asked Jan 7 at 12:02

deepblue_86

5851023

asked Jan 7 at 12:02

deepblue_86

5851023

The first 4 bytes of the compressed file or of the uncompressed file?

– PerlDuck
Jan 7 at 12:04

compressed file

– deepblue_86
Jan 7 at 12:05

add a comment |

The first 4 bytes of the compressed file or of the uncompressed file?

– PerlDuck
Jan 7 at 12:04

compressed file

– deepblue_86
Jan 7 at 12:05

The first 4 bytes of the compressed file or of the uncompressed file?

– PerlDuck
Jan 7 at 12:04

compressed file

– deepblue_86
Jan 7 at 12:05

add a comment |

2 Answers
2

active

oldest

votes

Here the code to take first four character of filenames;

filename=ANKR00TUR_R_20183350000_01D_30S_MO.crx.gz

tmp=${filename:0:4}

echo $tmp

Result:

echo "$tmp"



ANKR

Source

For a list

    for file in ./*.gz

    do

       echo "${file:2:4}" | tee -a list.txt

    done

previous for cycle will print on the screen the result and also append to list.txt

Source from Documentation on The Linux Documentation Project (TLDP)

Update
Improvement of code based on @steeldriver suggestion in comment.

edited Jan 7 at 13:40

answered Jan 7 at 12:17

AtomiX84

68019

How can I define 'filename' for all the files (apprx 300) and apply the above code?

– deepblue_86
Jan 7 at 12:19

they are all in a directory?

– AtomiX84
Jan 7 at 12:20

yes they are all in a directory.

– deepblue_86
Jan 7 at 12:20

1

Don't use $(ls *.gz) - see Bash Pitfalls #1

– steeldriver
Jan 7 at 13:19

thanks @steeldriver, I'm always get enough lucky and never encountered problems describe in the link you provide. I have improved the answer based on your suggestion.

– AtomiX84
Jan 7 at 13:41

add a comment |

To fetch the first N bytes of a string, cut can be used:

echo ANKR00TUR_R_20183350000_01D_30S_MO.crx.gz | cut --bytes=1-4 > output

This will extract the first 4 bytes from the given string and store it in the file output.

To apply the above code to multiple filenames, use

ls *.gz | cut --bytes=1-4 > output

edited Jan 7 at 12:37

answered Jan 7 at 12:09

PerlDuck

5,86211333

I applied the command but it produced compressed output file and it cannot be extracted.

– deepblue_86
Jan 7 at 12:13

Yes, that is exactly what you asked for in your question: The first four bytes of the compressed file. Or do you mean the first four bytes of the filename (i.e. ANKR) which is a different case?

– PerlDuck
Jan 7 at 12:14

yes, i meant the first four bytes of the filename (i.e. ANKR)

– deepblue_86
Jan 7 at 12:16

@deepblue_86 I updated my answer. Now it fetches the first 4 bytes of the filename instead of the file content.

– PerlDuck
Jan 7 at 12:20

1

@deepblue_86 Please don't ask follow-up questions in comments. Edit your post instead and clarify what you actually need.

– PerlDuck
Jan 7 at 12:26

add a comment |

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2 Answers
2

active

oldest

votes

2 Answers
2

active

oldest

votes

Here the code to take first four character of filenames;

filename=ANKR00TUR_R_20183350000_01D_30S_MO.crx.gz

tmp=${filename:0:4}

echo $tmp

Result:

echo "$tmp"



ANKR

Source

For a list

    for file in ./*.gz

    do

       echo "${file:2:4}" | tee -a list.txt

    done

previous for cycle will print on the screen the result and also append to list.txt

Source from Documentation on The Linux Documentation Project (TLDP)

Update
Improvement of code based on @steeldriver suggestion in comment.

edited Jan 7 at 13:40

answered Jan 7 at 12:17

AtomiX84

68019

How can I define 'filename' for all the files (apprx 300) and apply the above code?

– deepblue_86
Jan 7 at 12:19

they are all in a directory?

– AtomiX84
Jan 7 at 12:20

yes they are all in a directory.

– deepblue_86
Jan 7 at 12:20

1

Don't use $(ls *.gz) - see Bash Pitfalls #1

– steeldriver
Jan 7 at 13:19

thanks @steeldriver, I'm always get enough lucky and never encountered problems describe in the link you provide. I have improved the answer based on your suggestion.

– AtomiX84
Jan 7 at 13:41

add a comment |

Here the code to take first four character of filenames;

filename=ANKR00TUR_R_20183350000_01D_30S_MO.crx.gz

tmp=${filename:0:4}

echo $tmp

Result:

echo "$tmp"



ANKR

Source

For a list

    for file in ./*.gz

    do

       echo "${file:2:4}" | tee -a list.txt

    done

previous for cycle will print on the screen the result and also append to list.txt

Source from Documentation on The Linux Documentation Project (TLDP)

Update
Improvement of code based on @steeldriver suggestion in comment.

edited Jan 7 at 13:40

answered Jan 7 at 12:17

AtomiX84

68019

How can I define 'filename' for all the files (apprx 300) and apply the above code?

– deepblue_86
Jan 7 at 12:19

they are all in a directory?

– AtomiX84
Jan 7 at 12:20

yes they are all in a directory.

– deepblue_86
Jan 7 at 12:20

1

Don't use $(ls *.gz) - see Bash Pitfalls #1

– steeldriver
Jan 7 at 13:19

thanks @steeldriver, I'm always get enough lucky and never encountered problems describe in the link you provide. I have improved the answer based on your suggestion.

– AtomiX84
Jan 7 at 13:41

add a comment |

Here the code to take first four character of filenames;

filename=ANKR00TUR_R_20183350000_01D_30S_MO.crx.gz

tmp=${filename:0:4}

echo $tmp

Result:

echo "$tmp"



ANKR

Source

For a list

    for file in ./*.gz

    do

       echo "${file:2:4}" | tee -a list.txt

    done

previous for cycle will print on the screen the result and also append to list.txt

Source from Documentation on The Linux Documentation Project (TLDP)

Update
Improvement of code based on @steeldriver suggestion in comment.

edited Jan 7 at 13:40

answered Jan 7 at 12:17

AtomiX84

68019

Here the code to take first four character of filenames;

filename=ANKR00TUR_R_20183350000_01D_30S_MO.crx.gz

tmp=${filename:0:4}

echo $tmp

Result:

echo "$tmp"



ANKR

Source

For a list

    for file in ./*.gz

    do

       echo "${file:2:4}" | tee -a list.txt

    done

previous for cycle will print on the screen the result and also append to list.txt

Source from Documentation on The Linux Documentation Project (TLDP)

Update
Improvement of code based on @steeldriver suggestion in comment.

edited Jan 7 at 13:40

answered Jan 7 at 12:17

AtomiX84

68019

edited Jan 7 at 13:40

answered Jan 7 at 12:17

AtomiX84

68019

answered Jan 7 at 12:17

AtomiX84

68019

answered Jan 7 at 12:17

AtomiX84

68019

How can I define 'filename' for all the files (apprx 300) and apply the above code?

– deepblue_86
Jan 7 at 12:19

they are all in a directory?

– AtomiX84
Jan 7 at 12:20

yes they are all in a directory.

– deepblue_86
Jan 7 at 12:20

1

Don't use $(ls *.gz) - see Bash Pitfalls #1

– steeldriver
Jan 7 at 13:19

thanks @steeldriver, I'm always get enough lucky and never encountered problems describe in the link you provide. I have improved the answer based on your suggestion.

– AtomiX84
Jan 7 at 13:41

add a comment |

How can I define 'filename' for all the files (apprx 300) and apply the above code?

– deepblue_86
Jan 7 at 12:19

they are all in a directory?

– AtomiX84
Jan 7 at 12:20

yes they are all in a directory.

– deepblue_86
Jan 7 at 12:20

1

Don't use $(ls *.gz) - see Bash Pitfalls #1

– steeldriver
Jan 7 at 13:19

thanks @steeldriver, I'm always get enough lucky and never encountered problems describe in the link you provide. I have improved the answer based on your suggestion.

– AtomiX84
Jan 7 at 13:41

How can I define 'filename' for all the files (apprx 300) and apply the above code?

– deepblue_86
Jan 7 at 12:19

they are all in a directory?

– AtomiX84
Jan 7 at 12:20

yes they are all in a directory.

– deepblue_86
Jan 7 at 12:20

Don't use $(ls *.gz) - see Bash Pitfalls #1

– steeldriver
Jan 7 at 13:19

thanks @steeldriver, I'm always get enough lucky and never encountered problems describe in the link you provide. I have improved the answer based on your suggestion.

– AtomiX84
Jan 7 at 13:41

add a comment |

To fetch the first N bytes of a string, cut can be used:

echo ANKR00TUR_R_20183350000_01D_30S_MO.crx.gz | cut --bytes=1-4 > output

This will extract the first 4 bytes from the given string and store it in the file output.

To apply the above code to multiple filenames, use

ls *.gz | cut --bytes=1-4 > output

edited Jan 7 at 12:37

answered Jan 7 at 12:09

PerlDuck

5,86211333

I applied the command but it produced compressed output file and it cannot be extracted.

– deepblue_86
Jan 7 at 12:13

Yes, that is exactly what you asked for in your question: The first four bytes of the compressed file. Or do you mean the first four bytes of the filename (i.e. ANKR) which is a different case?

– PerlDuck
Jan 7 at 12:14

yes, i meant the first four bytes of the filename (i.e. ANKR)

– deepblue_86
Jan 7 at 12:16

@deepblue_86 I updated my answer. Now it fetches the first 4 bytes of the filename instead of the file content.

– PerlDuck
Jan 7 at 12:20

1

@deepblue_86 Please don't ask follow-up questions in comments. Edit your post instead and clarify what you actually need.

– PerlDuck
Jan 7 at 12:26

add a comment |

To fetch the first N bytes of a string, cut can be used:

echo ANKR00TUR_R_20183350000_01D_30S_MO.crx.gz | cut --bytes=1-4 > output

This will extract the first 4 bytes from the given string and store it in the file output.

To apply the above code to multiple filenames, use

ls *.gz | cut --bytes=1-4 > output

edited Jan 7 at 12:37

answered Jan 7 at 12:09

PerlDuck

5,86211333

I applied the command but it produced compressed output file and it cannot be extracted.

– deepblue_86
Jan 7 at 12:13

Yes, that is exactly what you asked for in your question: The first four bytes of the compressed file. Or do you mean the first four bytes of the filename (i.e. ANKR) which is a different case?

– PerlDuck
Jan 7 at 12:14

yes, i meant the first four bytes of the filename (i.e. ANKR)

– deepblue_86
Jan 7 at 12:16

@deepblue_86 I updated my answer. Now it fetches the first 4 bytes of the filename instead of the file content.

– PerlDuck
Jan 7 at 12:20

1

@deepblue_86 Please don't ask follow-up questions in comments. Edit your post instead and clarify what you actually need.

– PerlDuck
Jan 7 at 12:26

add a comment |

To fetch the first N bytes of a string, cut can be used:

echo ANKR00TUR_R_20183350000_01D_30S_MO.crx.gz | cut --bytes=1-4 > output

This will extract the first 4 bytes from the given string and store it in the file output.

To apply the above code to multiple filenames, use

ls *.gz | cut --bytes=1-4 > output

edited Jan 7 at 12:37

answered Jan 7 at 12:09

PerlDuck

5,86211333

To fetch the first N bytes of a string, cut can be used:

echo ANKR00TUR_R_20183350000_01D_30S_MO.crx.gz | cut --bytes=1-4 > output

This will extract the first 4 bytes from the given string and store it in the file output.

To apply the above code to multiple filenames, use

ls *.gz | cut --bytes=1-4 > output

edited Jan 7 at 12:37

answered Jan 7 at 12:09

PerlDuck

5,86211333

edited Jan 7 at 12:37

answered Jan 7 at 12:09

PerlDuck

5,86211333

answered Jan 7 at 12:09

PerlDuck

5,86211333

answered Jan 7 at 12:09

PerlDuck

5,86211333

I applied the command but it produced compressed output file and it cannot be extracted.

– deepblue_86
Jan 7 at 12:13

Yes, that is exactly what you asked for in your question: The first four bytes of the compressed file. Or do you mean the first four bytes of the filename (i.e. ANKR) which is a different case?

– PerlDuck
Jan 7 at 12:14

yes, i meant the first four bytes of the filename (i.e. ANKR)

– deepblue_86
Jan 7 at 12:16

@deepblue_86 I updated my answer. Now it fetches the first 4 bytes of the filename instead of the file content.

– PerlDuck
Jan 7 at 12:20

1

@deepblue_86 Please don't ask follow-up questions in comments. Edit your post instead and clarify what you actually need.

– PerlDuck
Jan 7 at 12:26

add a comment |

I applied the command but it produced compressed output file and it cannot be extracted.

– deepblue_86
Jan 7 at 12:13

Yes, that is exactly what you asked for in your question: The first four bytes of the compressed file. Or do you mean the first four bytes of the filename (i.e. ANKR) which is a different case?

– PerlDuck
Jan 7 at 12:14

yes, i meant the first four bytes of the filename (i.e. ANKR)

– deepblue_86
Jan 7 at 12:16

@deepblue_86 I updated my answer. Now it fetches the first 4 bytes of the filename instead of the file content.

– PerlDuck
Jan 7 at 12:20

1

@deepblue_86 Please don't ask follow-up questions in comments. Edit your post instead and clarify what you actually need.

– PerlDuck
Jan 7 at 12:26

I applied the command but it produced compressed output file and it cannot be extracted.

– deepblue_86
Jan 7 at 12:13

Yes, that is exactly what you asked for in your question: The first four bytes of the compressed file. Or do you mean the first four bytes of the filename (i.e. ANKR) which is a different case?

– PerlDuck
Jan 7 at 12:14

yes, i meant the first four bytes of the filename (i.e. ANKR)

– deepblue_86
Jan 7 at 12:16

@deepblue_86 I updated my answer. Now it fetches the first 4 bytes of the filename instead of the file content.

– PerlDuck
Jan 7 at 12:20

@deepblue_86 Please don't ask follow-up questions in comments. Edit your post instead and clarify what you actually need.

– PerlDuck
Jan 7 at 12:26

add a comment |

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