assistance with specific command in Bash -


i have proggram written in c 

argv[0]=command; argv[1]=null;  if(strcmp(command,"ls > try.txt")) {      dup2(fd,1);      close(fd);      execvp(command,argv);      perror("execvp");      exit(1); } execvp(command,argv); perror("execvp"); exit(1);

i want: if write ls >try.txt command work


Comments

Post a Comment

Popular posts from this blog

authentication - Mongodb revoke acccess to connect test database -

i have ec2 instance mongodb 3.2.0 installed. have user admin access. can connect user , perform operation remotely. 1 can connect database test remote if knows ip mongo 11.11.11.11. although not able make operations, want restrict access user credentials can connect server. first need create users , grant roles users, example: use admin db.createuser( { user: "myuseradmin", pwd: "abc123", roles: [ { role: "useradminanydatabase", db: "admin" } ] } ) then need start server --auth parameter mongod --auth more information here
Read more

python - GitPython: check if git is available -

gitpython depends on having command line version of git installed (otherwise, issue in question: oserror: [errno 2] no such file or directory on gitpython ). is there way gitpython api check if executable found, or, need wrap gitpython calls in exception handling account possibility? i don't particularly recommend this, did @ least once: try 1 git command while catching oserror case see if can run git (and running it, capture git version number well, in case). if git fails run, complain , disable further invocations of git (or exit or whatever). if not, assume further invocations continue work.
Read more

How to merge four videos on one screen with ffmpeg -

Image
this question has answer here: video grid vstack , hstack 1 answer i have video test.mp4, , need make appear 4 times @ once on screen. here found command makes 2 videos appear @ time ffmpeg -i input0.avi -vf "movie=input1.avi [in1]; [in]pad=640*2:352[in0]; [in0][in1] overlay=640:0 [out]" out.avi but doesn't work mp4 videos, , need 4 videos @ time. thank in advance four different inputs ffmpeg -i input0 -i input1 -i input2 -i input3 -filter_complex \ "[0:v][1:v]hstack[top]; \ [2:v][3:v]hstack[bottom]; \ [top][bottom]vstack,format=yuv420p[v]; \ [0:a][1:a][2:a][3:a]amerge=inputs=4[a]" \ -map "[v]" -map "[a]" -ac 2 output.mp4 two hstack instances make top , bottom, vstack combines those. amerge combines audio streams, -ac 2 downmixes them stereo. same input ffmpeg -i input \ -filter_complex ...
Read more