cat

问题 I have lots of text files and need to put a header on each one of them depending of the data on each file. This awk command accomplishes the task: awk 'NR==1{first=$1}{sum+=$1;}END{last=$1;print NR,last,"L";}' my_text.file But this prints it on the screen and I want to put this output in the header of each of my file, and saving the modifications with the same file name. Here is what I've tried: for i in *.txt do echo Processing ${i} cat awk 'NR==1{first=$1}{sum+=$1;}END{last=$1;print NR,last

问题 I have a namelist containing inputs for simulations. I have to change the path of some variables using bash. The text file has the following value that I would like to change: opt_path = '/home/gle/test_workflow', I would like to replace the value of opt_path with cat and sed, and I tried the following but it doesn't work: new_path=/my/new/path cat namelist.wps | sed "s/^opt_path.*/opt_path = '${new_path}'/g" it returns the following error: sed: -e expression #1, char 29: unknown option to `s

问题 I'm new to Linux and I'm looking for a command to merge files with the same name but from different folders. like this: folder 1, folder l1 folder 1 contains folder 2 and files 1.txt, 2.txt, 3.txt, ... folder 2 contains files 1.txt, 2.txt, 3.txt, ... I want to merge two texts from folder 1 and subfolder 2, then put them into folder l1. I got this: ls ./1 | while read FILE; do cat ./1/"$FILE" ./1/2/"$FILE" >> ./l1/"$FILE" done This one seems working well, two files are merged, however, a new

问题 I need to concatenate all files in a directory to one file, but files with specified names must be on top of the output. Just doing cat * > result will concatenate all files in alphabetical order. Is there any way to tell cat to place file vars.css or any other to the beginning of output? For now i just renamed files need to be first to 000-filename but i wonder if there is better solution without renaming files. 回答1: There are many ways to achieve this, most of which would involve invoking

问题 #!/bin/bash echo "print('Hello 1')" | python3 cat | python3 -u <<EOF print('Hello 2') EOF echo "print('Hello 3')" | python3 This outputs Hello 1 Hello 2 It will wait for me to press enter before printing the final Hello 3 . It does this also using python's -u flag for unbuffered output. Why does it do this for cat but not for echo ? 回答1: You aren't using cat. You're using a here-doc, and cat is waiting for input separately. Just remove the cat | and try it again. echo "print('Hello 1')" |

来源： https://stackoverflow.com/questions/34970182/simple-way-to-call-cat-from-c

问题 I have a bash script that produces some text from a pipe of commands. Based on a command line option I want to do some validation on the output. For a contrived example... CHECK_OUTPUT=$1 ... check_output() { if [[ "$CHECK_OUTPUT" != "--check" ]]; then # Don't check the output. Passthrough and return. cat return 0 fi # Check each line exists in the fs root while read line; do if [[ ! -e "/$line" ]]; then echo "Error: /$line does not exist" return 1 fi echo "$line" done return 0 } ls /usr |

问题 I would like to concatenate my files. I use cat *txt > newFile But I have almost 500000 files and it complains that the argument list is too long. Is there an efficient and fast way of merging half a million files? Thanks 回答1: If your directory structure is shallow (there are no subdirectories) then you can simply do: find . -type f -exec cat {} \; > newFile If you have subdirectories, you can limit the find to the top level, or you might consider putting some of the files in the sub

问题 I would like to combine files with similar ID before first underscore into one file using cat . How do I do this for multiple files like below? Thought of something like this: for f in *.R1.fastq.gz; do cat "$f" > "${f%}.fastq.gz"; done in 9989_L004_R1.fastq.gz 9989_L005_R1.fastq.gz 9989_L009_R1.fastq.gz 9873_L008_R1.fastq.gz 9873_L005_R1.fastq.gz 9873_L001_R1.fastq.gz out 9989.fastq.gz 9873.fastq.gz 回答1: for f in *_R1.fastq.gz; do cat "$f" >> "${f%%_*}.fastq.gz"; done >> for appending, ${f%%

问题 In order to see the console messages output by a function running in a foreach() loop I followed the advice of this guy and added a sink() call like so: library(foreach) library(doMC) cores <- detectCores() registerDoMC(cores) X <- foreach(i=1:100) %dopar%{ sink("./out/log.branchpies.txt", append=TRUE) cat(paste("\n","Starting iteration",i,"\n"), append=TRUE) myFunction(data, argument1="foo", argument2="bar") } However, at iteration 77 I got the error 'sink stack is full'. There are well